Hey, this isn't really pertinent to finding a decent spreadsheet, but I just found a port of the original VisiCalc spreadsheet program that was on really old IBMs. It has absolutely ZERO functionality, but it is cool to be able to see what was cutting edge back then. It runs in the DOS window in Windows. I am also happy to say that it is under 200 KB and runs great on a USB stick! Follow the directions on the site carefully.
http://www.bricklin.com/history/vcexecutable.htm
-Justin