The Game Genie is a fun accessory you can attach to NES games, which allows you to enter codes that alter the game. Some are just weird with no real purpose.

Below are scans from the Game Genie Booklet on Super Mario Bros. 3.
I'm from Canada (A Bilingual Nation) so it is in English and French.

If you know of any Game Genie codes not listed, please send them in.