Well the people at Console Classix have a damn good thing going on. If you download this program, you can play most Atari and Nintendo games free. It's damn cool! I played Contra, Super Mario 1, Mike Tyson's Punchout, Blades of Steel, and of course, Yar's Revenge tonight and man, it was nostalgic!
So if you are interested follow the link. It seems pretty safe, as none of my 2 computers have crashed yet! Check it out!