My father recently retired a 1-Ghz AMD computer with 1 Gbyte of RAM that he'd built from mail-ordered parts. He'd dropped the cash for a new Dell with Vista, which he likes quite a lot (no grousing, please, it happens), and let me have the old machine. My first move: Wipe it clean, install Linux, and prepare it for an exercise in "hand-me-down computing."
"Hand-me-down computing" sounds like a derogatory term, but it really isn't. I can't count the number of times in the past decade that I've given away computer hardware that I know I won't be able to sell for much of anything. Some of it is perfectly good stuff -- it's just old, takes up space, and there's only so many test machines I can have lying around. Why not give it to someone else who can make the best of it?
Most such machines shipped with Windows but no longer have any of the original licensing material, so it makes sense to mop them down and install Linux. The exact choice of distribution varies with the hardware -- I fitted my ancient creaking battleship of a Pentium laptop with Damn Small Linux when I gave that away -- but this is another situation where the breadth of Linux distros out there is immensely helpful. There are some distributions I would not put on a machine I was giving to a relative newcomer (Gentoo? not a chance), but most of the popular distributions seem to at least work tolerably well on machines even four or five years old as long as you don't go in with unrealistic expectations.
What better way to find out how Linux performs for a relatively nondemanding user? I've got a couple of likely recipients for this particular machine already in mind, most of whom fit a basic profile: They don't have a lot of money, either for a new machine or commercial software to put on it, and they don't have terribly high demands. They just need something that works for the basic computing they do, and a hand-me-down with Linux and its associated applications fits that bill perfectly. (I think now of the For Sale ad I once saw for a 12-year-old Econoline van: "Runs. Best offer.") In very few cases are they wholly dependent on something specific to Windows, and the few times they are it's not hard to work around that.
Another option I've employed in the past is to donate the computer to a nonprofit organization such as The Surplus Exchange or Computers With Causes, but I know enough people in my immediate circle of folks who need something that I hardly mind letting them have first crack at what I've got to offer.
Have you recycled a machine lately, with or without Linux as an aftermarket add-on?