2. Protect your brand new watch
Okay, this doesn't make a ton of sense to us, but on almost every forum or article discussing alternate condom uses, someone mentioned that a condom can waterproof a watch in a pinch. So if you're caught in the rain with a beautiful Jaeger-LeCoultre Reverso—or this Seiko homage (ish)—you can put it in a condom and stick it in your pocket. Or you can just do it on the wrist like this.
3. Make a slingshot
This simple trick involves a plastic cup, a Jimmy-cap, and ammunition. Cut a hole in the top of a plastic cup, roll that dinger over the top, drop in a penny, pull back, and put out someone's eye.