Lock a Deadbolt without a Key

I found this fun Instructable today that shows you how to lock a dead­bolt with­out hav­ing the key. I can think of a few sit­u­a­tions where this could come in handy:

• You are at a friend’s house and they leave you home alone but for­get to give you a key (or they give you the wrong one). You can’t leave the house unlocked, so that means you are stuck at home until they get back.
• You can lock your co-worker’s or roommate’s door to confuse/anger them.

Hmm.. I sup­pose those are the only sit­u­a­tions I can think of where this would be useful…

Any­ways, all you need is some tape (clear pack­ing tape works great). Take about a yard of tape and fold it in half so that only a few inches on the end are still sticky. Securely attach the sticky end to the dead­bolt knob, hold on to the other end, step out­side, and shut the door. Pull the tape so the knob turns. Once the door is locked, tug on the tape so it breaks off so you don’t have a strip of tape hang­ing out of your door.

I tried it a few min­utes ago and it was very easy to do and very effective.