This story originally appeared April 12, 2008.

When the day's work hassles are over, many PCs don't shut down, they simply downshift to other deeply engaging worlds. For some people that means volumes of video and music downloads. For others, the soothing balm that makes the day's worries melt away is video gaming.

Anyone who thinks video games are for kids, hasn't seen the results of a recent survey from AOL and the Associated Press:

"It's not about eating dots and shooting pixilated aliens anymore," said Ralph Rivera, Vice President of AOL Games in a statement.

So what is gaming for grown-ups all about? It's about epic historical adventures; futuristic quests; wizards, trolls, and assassins; cinematic military conflicts; dazzling mental jousts, and much, much more.

We've compiled a list of the top video games. Our criteria: No kiddy-fluff topics or characters, an emphasis on deep layers of strategic or tactical thinking, interesting story-telling, and lots of replay value. If you're already an avid gamer, you might find one you haven't yet tried. And if you've never played, there's no better place to start than this list:

8

World of Warcraft

Blizzard Software

Price: $15/month

Pros: Allows you to exercise your inner Dungeons & Dragons nerd. Extremely easy to play and it is an excellent way to combine socializing and gaming.

Cons: Addictive. Can take over your life to a destructive degree if you’re not careful.

It is with a certain amount of trepidation that I recommend Blizzard’s epic online game because it has single-handedly ensnared more than 10 million PC gamers into its web of highly addicting fun. In the gaming business, that's called that a good problem.

What is it that makes World of Warcraft so special? Three of the biggest reasons are: 1) It feels like you’re playing in an epic Tolkien-esque adventure; 2) It allows you the ability to play with other people; and 3) it allows you to indulge your innate need to collect things.

The way the game works is simple. You start off by creating a character. In classic Dungeons and Dragons style, you can choose between a fighter, magic user and numerous other character types. After naming the character, you join the world and begin playing immediately. What you do and who you do it with is entirely up to you, but it will likely involve slaying monsters of some kind.

One of World of Warcraft’s greatest strengths is that is extremely easy to play, so much so that everyone from children to 70-year old grandmothers have become hooked. It’s worth a try -- particularly if you’re interested in the ins and outs of virtual living.

7

Desktop Tower Defense

Hand Drawn Games

Price: FREE

Pros: Simple-to-learn…but entertainingly difficult to master; it’s free!

Cons: Lack of deep story and photorealistic graphics reduces the appeal for hardcore gamers.

One of the biggest contemporary trends in computer gaming these days is the migration to so-called "casual" games. Casual games are entertainment experiences that are considered to be less complex than a full-blown, boom-pow PC or console game. Mobile games are the most ubiquitous example of casual gaming. Other examples are games that are built in Flash and are fully playable from within a web browser.

Desktop Tower Defense is one of these browser-based games. Over the last two years, very few games have exceeded its popularity or durability. Literally millions of people have played this easy-to-grasp puzzle/strategy title. The gameplay is simple: A number of enemies (named "Creeps") are trying to infiltrate your space. You build a series of towers and tower upgrades to stop them. Killing the creeps earns you gold; this gold can be used to build more towers and upgrades.

The appeal of DTD is two-fold. First, anyone with a web browser can play it -- there’s no need for sophisticated overpowered PC hardware. Second, it’s free. You can play right now by clicking >here.

6

Orange Box

Valve Software

Price: $49.99

Pros: Five games in one; gorgeous graphics; and Portal is one of the best games of 2007.

Cons: With the exception of Portal, the gameplay can be fairly aggressive and requires fast-twitch reflexes.

If you’ve recently seen or heard the saying "There is no birthday cake" in people’s email or message board sigs and wondered what this quote means, the answer lies in Valve Software's recently released Orange Box game set.

Orange Box is a steal because it contains five complete games. Half-Life 2 and two follow-up episodes, plus a multiplayer game called Team Fortress 2, and the crown jewel of the Orange Box, a game called Portal. The first four games would be well worth anyone’s money. Half-Life is a stellar action adventure game set in a dystopic future. You play the role of Gordon Freeman, and your job is to help liberate a city from the grips of oppression. The story twists and turns and you fight all manner of enemies, villains and monsters with all kinds of weapons. And while the gameplay can be pretty fast-twitch oriented, a unique blend of creative story-telling makes it all worthwhile.

Team Fortress 2 takes the basic gameplay in Half-Life 2 into the online multiplayer arena. The nice thing about TF2 is that, in comparison to other multiplayer action games, it is an extremely straightforward fast-paced affair.

But again, the real gem is Portal, one of the most talked about computer or video games of 2007. Originally developed by a couple of game design students, the game eschews guns and combat for a series of mentally challenging action puzzles. It takes about 5 hours total time and the ending is worth the price of the entire Orange Box set.

5

Assassin's Creed

Ubisoft

Price: $49.99

Pros:Game gives players excellent nuanced control over character movements.

Cons: Sneaking around assassinating people isn’t for everyone.

If you've ever found yourself thinking that games are child's play, 5. Assassin's Creed should tickle your fancy. How about this for a mature, rich story line? In Assassin’s Creed (originally released for the Xbox 360 and PS3, but now available for the PC) you get to play a Muslim assassin responsible for the killing of all kinds of people -- including Christian Crusaders -- during the Crusades. If that is not a proper plot and story for adults, what is?

In Assassin's Creed, you play the role of Altair, said assassin. Altair doesn’t talk much, but he’s an extremely talented guy and the game creates some interesting situations for him. When he's preying upon a victim -- most of the adventure is a series of assassination attempts -- he can approach the kill in a number of ways. Not surprisingly, stealth is imperative, but it takes multiple forms. You can disguise yourself by blending in with a crowd. Or you can prowl upon the rooftops -- just be careful not to draw attention from the populace. You can hide in the shadows. You can also approach your target in brazen fashion, but the end result is almost always bad.

One of the most unique attributes of Assassin’s Creed is the way you control your character. Instead of using simple button presses like attack and jump and run, you use a more subtle approach. Different buttons control different parts of your body -- head, legs, arms -- and other buttons control the intensity and aggression with which you use these body parts. It all adds up to a very interesting and unique experience.

4

Nintendo Wii

Nintendo

Price: $250

Pros: One of the most unique and innovative gaming systems; fun for the whole family.

Cons: Graphics quality isn’t as high as many PC games.

The presence of Nintendo's Wii on this list isn't mean to provoke or detract from the fact that there are lots of great PC games out there. It’s more of a subtle reminder that at their best, games are supposed to involve on key activity: having fun.

Over the last two years, Nintendo has completely revamped everyone’s expectations of what interactive entertainment can be. The company’s new gaming system, the Wii, has been nothing short of a revelation. The genius stroke: Nintendo’s decision to eschew hard-core gamers’ demands that a new video game console embrace high-end state-of-the-art computing and graphical processing power in favor of an innovative and immersive control scheme.

The end result is a system that emphasizes natural action as opposed to the thumb-and trigger-finger based. In Wii Sports, you swing the Wii controller as if it were a tennis racket and when you do, the on-screen characters’ actions mimic your own. Later this year Nintendo will release Active Life: Athletic World which will use a new floor mat controller, for an even more vigorous workout.

This intuitive control scheme has profound implications for video games. Suddenly, seniors, parents, and children are all playing together again, an occurrence not seen since the days of the Atari 2600. So…while the Wii isn’t necessarily a solitary endeavor, you can consider it a nice investment for your entire family. After all, when’s the last time you all got together for some good old-fashioned fun?

3

Call of Duty 4

Gamespot

Price: 49.99

Pros: Riveting, realistic action. Spectacular graphics.

Cons: Not for pacifists.

If you like playing traditional "shooter" games -- action-oriented experiences viewed from the first-person perspective where you sprint between locations shooting your enemies-- you probably already know the Call of Duty series of games. Set during the WWII era, the first Call of Duty was released several years ago exclusively on the PC platform and garnered rave reviews from critics and everyday gamers alike.

Released for the PC platform in late 2008, the award-winning fourth incarnation of this now-legendary series makes a leap forward in time to the modern era. The end result is a work of beauty that feels more like an old-school Tom Clancy novel than a video game.

Call of Duty 4 posits a series of events that trigger a bloom of terrorism in Russia and in the Middle East. You take control o f several soldiers from United States and European forces. The action is extremely fast-paced and boasts an intensity and visual clarity that is virtually cinematic. In a stroke of genius that less experienced gamers will appreciate, the game features an extremely basic difficulty level that just about anyone can play. This is one of those rare experiences that has to be seen to be believed. The high point of the game is an eerie mission where you man the heavy gun on an attack chopper that is depicted in grainy black and white.

2

Elder Scrolls IV: Oblivion

Bethesda Softworks

Price: $39.99

Pros: Open-ended role-playing game allows you to play however you want; epic D&D style experience.

Cons: If you’re not into wizards and trolls, Oblivion is not for you.

For many tech enthusiasts, Dungeons & Dragons and PC gaming are a natural fit, so we’d be remiss if we didn’t place one of the most epic fantasy role-playing adventures of the last 10 years on this list: Elder Scrolls IV: Oblivion .

Elder Scrolls IV: Oblivion is so immersive it feels like you’re playing in a movie. The story gets set up with a manic struggle to protect an escaping king. Once this mad dash ends however, what happens next is up to you. You can cast magic or do battle, fight with swords, or become a thief. You can join various guilds and take on missions for them.

You can also just move between towns interacting with village and city folk, undertaking various quests in assistance. Here’s an example: In one of the towns in the world, you’ll encounter a man who is concerned about his friend’s behavior. He asks you to confront the man or speak to the guards. If you do neither, he’ll kill his wife out of jealous spite.

This is one of those rare games that you can play for at least 100 hours without becoming bored. And if you really enjoy it, you can and should be sure to purchase the Shivering Isles add-on, which was released last year.

1

Civilization IV

2K Games

Price: $49.99

Pros: Incredibly deep gameplay that simulates the course of history. You can play it with your kids because there is no blood and gore.

Cons: Games take a long time to play. Fairly complex initially.

Now in its fourth incarnation on the PC, Civilization IV is easily one of the greatest games of all time and a near perfect game for intellectual gamers. The pacing is more akin to a board game than most computer and video games these days.

The game begins with you choosing a historical people from a lengthy list (Americans, Egyptians, Greeks, Native Americans, and many more). Then you take control of a single band of settlers. In your first few turns you have to choose where to build your first settlement. From this point on, you get to completely dictate your people’s destiny. You do this by making a litany of decisions. Do you build a granary to help feed their bellies? Or a church to feed their souls? Or an army to hold them back and conquer other nations? Like any leader, you’ll have to utilize a blend of all three. You win the game by dominating the world politically, diplomatically, economically, or militarily.

One of the most interesting elements of Civilization IV is that it takes hours and hours to play. The pace is leisurely, but the level of engagement and intensity of decision-making is so intense that it’s not uncommon for players to look up from their PCs in horror to discover that it’s 3:30 in the morning on a weeknight. If that isn’t the most ringing endorsement for a game, I don’t know what is.