Not convinced? Alright. StickNFinds are bluetooth coin-like things that you can stick to anything you want. Using a cellphone app, you can locate those stickers, make them beep, use a radar screen to point you towards them, and more. Here: Go contribute.
Awesome, right? Here's the Indiegogo link again.
My biggest question is whether you can sync multiple phones to the same sticker -- so that, for example, we could put one on my mother's phone, and make both my dad's and my phones detectors to find it. I asked in a comment, and will report back if I find out.