Remember the Android Developer Challenge? Google offered up some prize money to those who submit the best applications for the Android platform. Today, Google said it has whittled the 1,788 entries it received down to the top 50. Each of them earned a $25,000 initial prize, but just what makes a good Android application?

Kudos to the top 50. No one knows exactly what criteria Google used to judge these applications, but reducing a pile of 1,788 entries down to 50 is no small feat. Google said it was looking for applications that are "cool and delight mobile users." Since cool is subjective, I am sure some very decent applications were left in the slush pile. As for the top 50, each will receive $25,000 and is eligible to receive further recognition via 10 $275,000 awards and 10 $100,000 awards in the final judging round.

Google has posted the names of the applications and their authors, but not much more than that. Even so, we're able to infer a little bit about what the applications do based on their names. Let's round up a few categories.

LBS: There's no shortage of what appear to be location-based services and GPS-enabled applications. With application names such as: BreadCrumbz, gWalk, Locale, PedNav, PocketJourney (Don't stop, believin'!), City Slikkers, and TeraDesk, we're sure to be able to find our way from point A to point B with Android handsets, once they become available. And we're not just talking driving directions. Being able to find things while on foot in unfamiliar surroundings is just as important as while in the car.

Security: There are more than a few security-minded applications in the top 50. Several of them look like they are counting on biometric scanners to be built into the hardware as well. BioWallet could make use of a fingerprint scanner to open banking functions. Fingerprint could do the same thing, or even just unlock the phone from a locked state.

Safety: Safety applications go hand in hand with security applications, and there are several of those as well. FreeFamilyWatch will probably help you keep tabs on your family members' locations. CallACab will help you avoid being pulled over and given summons for DUI. Safety Net and LReady Emergency Manager could do anything, really. Those two are a bit too vague, though helping find the closest ER doesn't seem to be out of the question.

Personal Productivity: There are a bunch of apps that look like they are designed to help you manage your personal info. Something such as Phonebook 2.0, Cooking Capsules, Writing Pad, PicSay, and LifeAware may all enable you to keep tabs on your daily activities.

Social Networking: What would a new smartphone platform be if it didn't support social networking applications? There are a handful in Google's top 50. IMEasy looks like a IM app, as does Multiple Facets Instant Messenger. Others, though, look like they will tie into MySpace and Facebook. Sustain-Keeping Your Social Network Alive is pretty self explanatory. SocialMonster sound a bit more exciting.

Toss Ups: Then there are a bunch of apps that I just can't put any sort of function to at all. Anyone's guess is as good as mine with names such as: AndroidScan, Beetuan, Commandro, Dyno, e-ventr, Em-Radar, Jigsaw, JOYity, Marvin, Mobeedo, PiggyBack, Rayfaria, and SplashPlay.

In all, it looks like the applications cover the gamut of possibilities. I can't wait to try them out on an Android handset.