Rayman 2: Revolution Codes -

Unlock Cheat mode:
Goto the options screen in any of the maps (excluding the first map) and choose Sound, highlight the Mute option, now press and hold + and push , , , , , . A cheat menu is unlocked and will be visible if the code has been entered correctly.

Secret multi-player maps:
Go to the options screen in the first map and choose Language,  now choose Voices. Highlight the "Raymanian" option, then press and hold + and push , , , , , . Three additional multi-player maps will be unlocked if the code has been entered correctly.

Unlock Baby Soccer secret map names:
While playing baby soccer, press and hold + and push , , , , , .