Portal Theme Done on 8080 and C64
If you've played Portal then seeing this video brings everything full circle. The retro computers inspired the closing song "Still Alive" which has then inspired someone to recreate the song on retro computers. It's geektastic and was done on an Intel 8080 with a C64 sound chip.
If you haven't played Portal yet and you're even remotely into games, then beg, borrow, or steal a few hours on a machine to play it. It's lovely.