Insert Coin semifinalist: Mr. Postman brings snail mail to your smartphone

As a general rule, we're in favor of any gadgets named for one of our favorite girl group jams. We've also got a soft spot for those projects looking to send a little love in the postal service's direction -- lord knows it can use it. Mr. Postman, naturally, fulfills both of those quotas. The smart mailbox communicates with your handset to let you know when mail has arrived. You can also use the app to lock and unlock your mailbox, to ward off those pesky neighborhood mail thieves. Now if only there were a high-tech way to tell them to get off your lawn.

You can see all of the Insert Coin semifinalists here.