From the map screen, input:

unlockall - Unlocks all the maps for that difficulty.
relockall - Locks all the maps for that difficulty.

During the game, input:

double - Double all friendly armies.
half - Havles all enemy armies.
empty - Empty all enemy countries of armies.
booth - Strengthen your enemies.
woohoo - Ear candy.
explode - Eye candy.
winmap - Wins the currently playing game.
command-left - Go to the previous map
command-right - Go to the next map.