(Video Link)
John Kestner and other MIT students designed the Proverbial Wallet. It provides tactile feedback about the state of the user's finances. Whenever there's a bank transaction, it vibrates. As the user's bank account grows, it swells. As money is depleted, it compresses. A hinge tightens as the user approaches a financial goal, discouraging further spending.
Link via Gizmodo
Yeah, that's oh so much better then just looking at your bank balance on your smartphone.