Wow, isn't it the wrong season for this? We always do this in October.

Anyway, here's how you get them back: Take some vasoline and put it under the handle on their car doors. When they go to open their door, their fingers will pop and they'll feel like they've broken their fingers.

-OR-

Find some roadkill. Get under their cars and put it right above their Catalyac convertor, make sure you get it where it won't move when they drive. This will cause such a stink they can't bear it, and they'll never be able to find the stinch for a few weeks until it's gone.

Remember these are a friends copywrited moves.