Tetris and Friends
Get Tetris (and several other classic Windows games) in the Best of Windows Entertainment Pack.
Download the Zip file HERE , unzip and run SETUP (if it doesn't do it automatically) and it'll even put it in your Programs Menu.
I've had it work on Windows 98 and 2000 just fine. Just keep in mind that whenever you play, it turns off the NumLock on your keyboard.