You might have forgotten to get milk again, but at least you won't forget your car keys, thanks to the hipKey from Hippih. Simply attach the aluminum-and-plastic disc to your item of choice and sync with the hipKey iPhone app to start keeping tabs. An alarm will sound if your stuff drifts too far away (you can choose an alarm distance of up to 164 feet) and if you misplace it, just hit the "Find Me" option on your app to locate your wayward wallet.
Sick of your roommates "borrowing" your car without asking? Put the hipKey on Motion mode and the 90 dB alarm will decimate their eardrums when they go after your keyring.