If you were a fan of the Commodore 64, you should know that an emulator has now been released on the iPhone. The emulator is completely legal, and comes shipped with 5 roms/games: Dragons Den, Le Mans, Jupiter Lander, Arctic Shipwreck, and Jack Attack. There will be additional games added periodically.
There were problems with the release because of code that allowed arbitrary code to be run using the program. Once that was cleaned up, Apple approved the emulator which has full licensing and is 100% legal.
Enjoy this video showing off some games that will be available soon from the app. The app is currently at $4.99, and you can find the app store link here.