Crap, I trashed my Compaq's 486/66 as soon as the hard drive in the comp died. Oh well. BTW, a shotgun may be fun, but it doesn't beat the thrill of playing compu-golf...with a sledge.
I'd be on the lookout on ebay. They most likely have stuff you'll be looking for. You could go out and look for some REALLY old chips, like a Zilog-80 (think TRS-80 computers), but those are fairly common (used in TI graphing calcs). Old montorola chips could be a good place to start. If you want really rare, get the first Intel Microprocessor (I think the 4086 or something like that). Now THERE was technology. Measured in KHz. Mmmmmmm...........