NetHack, text Unix pwnage thing, extremely old, kinda fun. Err, modern games, probably Quake3, RTCW, Half-Life, RTCW: Enemy Territory. RTCW: ET is serious pwnage. BTW, if anyone wants a laugh, look what I did to Quake3:
And before you ask about the fps, I was experimenting with different fps caps to see which ones were better for trickjumping.