Are you like me and have played the nes super mario brothers games and beaten them countless times? If so, then here is something you might be interested in. It is a patched version of SMB 3 with all new levels, villians, and even a different game engine. An already patched version of the game can be found on this page:
If you would like to try out more of these, the following page has more, unpatched versions. All you have to do though is have an emu for nes (links provided on this site), and patch them with IPS patcher (also provided on this page).
Ever since I found these I've been addicted to them