The equivalent of drum practice pads for guitarists. PocketStrings are small bars with real guitar strings and real frets that you can use to practice anywhere. Available in 4- and 6-fret variants. Also on ThinkGeek.
A durable aluminum key ring that lets you fold keys similarly to how the tools in Swiss army knives are arranged. Special models include one with an integrated USB drive and one that can be expanded to carry up to 100 keys.
This waterproof flashlight can crank out a blinding 3500 lumens from a gadget that’s not much larger than the palm of your hand. Runs for up to 1000 hours with the right batteries. Though its hefty pricetag might break the bank.