'Accidentally' fall into shelves.

Head to the meat department, stand totally still, and fling meat at people the moment they walk by, and yell "YOU KILLED MY FATHER! PREPARE TO DIE!".

Same as above, but demolish their carts with hammers.

The moment someone lets go of a cart, steal it. Run like hell if you have to.

[s]Mix up the items on the shelves[/s] Never mind, that's normal for employees in my neighborhood walmart.

Use movies as frisbees.

'Sneak up' on cameras and smash them. Bonus points for looking sneaky and approaching in a mostly straight line.

Start putting on all the clothes you can get your hands on, especially the lingerie, and just start flinging everything you can't wear around.

Good old stalking, bonus points for being conspicuous.

Badly try and steal jewelry.