Some of those could get you arrested - like:

TP as much of the store as possible before they stop you.

Try to hold up customers with the toy guns. See how much you can make.
Destruction of property, etc. Security folks tend not to have a sense of humor about such things.

If I were bored in Wal*Mart, I'd just leave and do something more interesting.

A girl I used to know, Carol, was born with Spina-Bifida so was in a wheel chair. She is of at least average intelligence (with a wicked sense of humor), but, especially when she was a kid, everyone just assumed that she was mentally retarded, not just physically handicapped. When she was shopping somewhere with her mom, and got really bored, if asking her mom to leave didn't work, she'd sometimes tilt her head to the side and drool, so people would say "Oh, that poor child," and the like, and then, if her mother told her to cut it out, everyone would be shocked and scandalized that this "mean" woman was scolding the "poor retarded child." Carol said she always got in trouble once they got home, but it was worth it! Toldya she had a wicked sense of humor!