I miss having an old car -- a few years back I had recently moved overseas, and was driving a car I could reasonably buy with cash from the ATM (no bank account yet, etc). Well, one day I managed to lock my keys in the car (and myself, my wife and 2 friends out of it) while we were at the grocery store. I turned around, jogged back into the store, bought a screwdriver and a coat-hanger, and jogged back out. The screwdriver was to push the upper corner of the door away from the frame (easy to open a little space, but hard to do with just fingers); the coat hanger was to snag the lock and pull it up.

The hardest part was actually getting the screwdriver out of its damned unbreakable-but-dangerously-sharp plastic packaging.

All-in-all, we only got home about 5 minutes later than we would have!