Learning how to pick a lock can come in handy from time-to-time. Whether you get locked out of your house or lose the keys to your old bike lock. Sure you could solve either of those problems in a more aggressive manner, but why not learn how a lock actually works. There are plenty of cool resources available for learning how to pick locks. This particular tool is a clear padlock ($14) which can make understanding locks much easier. If nothing else it would make a cool conversation piece sitting on your desk.