Got a Gateway computer from a friend of mine. No word yet on whether it works, because I don't have a monitor or any cables on hand right now. This is the information I've managed to glean from serial numbers and so on:

Gateway Performance 1800CX
640MB RAM
Pentium 4 (probably 1.8GHz)
VisionTek nVidia TNT2 AGP (probably 16MB)
Creative AudioPCI 128D
Network & voice modem
CD-RW & floppy

It's got no HDD but it's just as well, because it originally came with WinME. *fart noise* It's got a sticker on the front saying "built for Windows 2000", so I imagine it'd run WinXP quite well. Another option: install Debian, and run WINE/DOSBox on top of that.