There is a way to still play C64 games, but this is done through downloading the game files that you used to own (having backup copies of your games is still legal, I think?)
Basically, you hook up C64 to your pc through some sort of port and have the C64 read from a directory in the PC.
Can't remember how it was done but I saw a clip of it being done on a tv show on Tech Tv or G4...
AHA! I found the original program segment that can help!
http://www.g4tv.com/screensavers/features/42459/The_Commodore_64_Is_Alive.html