iPhone: Are you constantly misplacing things or concerned when your young child or dog go wandering off? BiKN (pronounced like beacon) can track them down for you. BiKN is a case that pairs wirelessly with key fob-sized tags. With the system, your iPhone finds your stuff and your stuff can find your iPhone.
The most obvious use for BiKN is finding lost keys, but you can also use it to locate and protect other things. BiKN not only tracks items, it has a "leash" function that alarms you if the iPhone and tags are separated beyond a distance limit you set. That could make it a great alarm system for your laptop bag or if you want to make sure your kid doesn't wander too far away in the park (the range is supposed to be about 800 feet). There's also a "page" function that sends an alert to all the tagged people and/or animals.
The tags need to be charged every now and then, but because there's a battery in the case, BiKN doesn't drain your iPhone battery and it can work even if your phone is dead.
The system is only available now for the iPhone 4/4S; a new version fo iPhone 5 is in the works. One case and tag (both are can have customized colors) costs $99.99 and a starter kit with two tags is $129.99. Additional tags—you can have up to 8—cost $49.99 for two.
It's not cheap, but it's hard to put a price on always being able to find the stuff you care about.