Don't have any old computers to play around with? Don't worry, the power of emulation makes it possible for everyone to enjoy old computing!
 

ALTAIR - The first home computer. Although the computer never could do much, it's still fun to play around with the emulator. This one is for WIndows 95.

CP/M - Arguably better then MSDOS. Most CP/M emulators are really just emulators of the Z80, as is this one - MYZ80, and it's for DOS.

COMMODORE 64 - Definitly one of the best computers produced. It's sond and graphics was earth-shattering it's time. This emulator is the CCS64 for DOS.

That's all the emulators so far. I plan to have more soon!