NES Emulator March 2015
Supports USB joysticks and has an awesome game selection screen.
I never had an NES as a kid, but I did have a Commodore 64. I played lots of games on it, including Mario ripoffs. Some of my friends had a Nintendo, so I did have some exposure and was always fond of SMB3. Writing an emulator sounded fun and now I can play old Mario classics whenever I want. And yes, it can generate animated GIFs!