Set up a cluster folding or searching for Extraterrestrial Signals.
Run a server(s) for COunter Strike, web stuff etc.
Open up a Internet Cafe where you can play multiplayer games like CS, UT2k4 and Battlefeild 1942.
Give them away (ill have one)
Cannabalise them and sell the parts (ill buy some parts and pay shipping)
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.