There are loads of great emulators out there but there is a new emulator that allowed people to play NES games in a 3D perspective. The games themselves haven't been re-coded or altered but rather the backgrounds altered on the z-axis to give it a diorama look. The results are so-so but on some games they really pop, check out the video below of Mega Man and be prepared to be impressed!
Old Man Gameboy
My cousin forwarded me this picture and I thought I'd share it with you lovely people!