Got it today :P

Dell OptiPlex GX620 (Yes I know it sucks, you don't need to tell me :P )
Specs:
Pentium 4 HT 3.4Ghz (1 physical core, 2 "logical" cores)
2Gb of RAM
bla bla bla. thats the most important stuff.
The tower was $100, keyboard/mouse was $15, monitor was $5. Total $120 :D
Planned upgrades:
Well I already installed Windows 7 Ultimate 64-bit, runs great.
I REALLY need a wireless adapter card so I can connect to the internet. (Gonna pick one up after I get my tax return this week/get my paycheck this week)
Radeon HD 4670 to run some games.
2 more gigs of RAM.
A 1Tb hard drive.
A lot of the things I upgrade it with (HDD, wireless adapter, things like that) I'll use when I finally build my real computer.
Since I can't connect to the internet, I can't update my drivers. So I have no audio or video stuffs. Blockland won't even launch :P