Pranks

On Philosoraptor:

These Hummer owners who have vanity plates that reinforce their vanity deserve a little monkeywrenching. Now, I wouldn't advocate spray paint or other vandalism, but a toothpick holding open a tire valve is easy to get away with and merely a temporary though hopefully enraging inconvenience.

Bend over as if to tie your shoe, and this shouldn't take more than a few seconds. Do it on the driver's side so the idiot doesn't blithely drive away on three tires. You don't want anyone getting hurt by this.

Sure, a brick through the windshield might be more satisfying viscerally, but think how long you can laugh about this milder prank without joining your victim in assholery.