Hm, find a room, hook them up and run a SETI farm?
Find one of those foreign aid societies that takes computers and gives them to developing countries indigenes.
Find an organization that runs schools in foreign countries and donate them for the use in teaching students.
contact one of those womens interest groups that organizes villages female populations into collectives that sell handcrafted goods to the us, one computer to a collective would let the women get online [provided they could get electricity and a phoneline] to more effectively contact the rest of the world.
Are these PCs ones that you can take off of the company site yourself? If you’re allowed to take one home and you have a full-time static IP address there, you could do what I did with my old 200 MHz system (64MB RAM, 10 GB HD). I’m running that machine as a Linux server on which I can use as a low-traffic web server or web page. I can also FTP files to and from it from anywhere. I might later on set up another old machine to run as a mail server under Linux as well.
I like the distributed computing idea if you can’t donate them to a needy organization. There are many programs that are going on and there might be some possible benefit. There is an AIDS related program and cancer programs that I would check out. Maybe your company would like to sponsor something like that with these older machines.
Here’s another vote for donating them to someplace that can really use them. However, I have a slightly different suggestion. I have no idea where you’re located, so I’m doing hypotheticals: Call the School Board office of some nearby large city … or the county office of some low population area in the deep south, southwest or west (including some of the reservations that don’t have casinos). Almost any such is likely to have either no computers, very old computers (would you believe 286s?), or NO computers.
In any such case, you will be contributing to the future of kids who need the help, and maybe one of them will grow up to be a doctor, or a scientist, or a nurse in a nursing home, or …