I admit, video game hacks and cheat codes are fun.

However, some times crazy things are more impressive when they don't use traditional hacking or cheat codes. Case in point, (an admittingly glitchy version of) the original Super Mario Bros (with 8-bit graphics but Super Mario All Stars sound) in Super Mario World.

http://nach.tasvideos.org/smwsmb-tasv2-masterjun,nach.mkv

I assure you that this is real. If you have lsnes, an ordinary US SMW rom and this lsmv file, and stop it right after the smw portion ends, you could play it yourself.

edit: The same trick done on real hardware here.