Once you get a bunch of trophies, go to the stage in the Fun Bazar. When you're there, click parade. When the trophies go by, click on them so they'll do something special.
Main Menu Fun
Click on Characters pictures at the main menu to hear them say something. If you click on them a few times they will say something different. Mario's is the coolest because he will do something different each time (laugh, cheer, fall, etc...)