In Skate 3 for PS3 and Xbox 360, there are various cheat codes you can enter for some different (and interesting) effects.
Press Start > Options > Extras > Enter Cheat Code and type in the following
Deadspacetoo – Unlocks Isaac from Dead Space as a playable character
Mcfly – Your board becomes a hoverboard.. awesome!!
Miniskaters – Well.. you become a mini-skater
Streetsweeper – Reset all objects to their original spot
Zombie – Pedestrians turn into zombies that chase you.. and EAT YOUR BRAINS!!