If you like jewelry and are interested in applications for near field communication, an NFC ring could be right up your alley. John McLear is a British designer who makes rings that can interact with other NFC gizmos like door locks or mobile phones.
That means that this battery and charge-free ring can be used to unlock doors, share information with friends, and lots more. McLear's creation has two separate transmitters: one can share public information, and the other can store private data. The software is open source, too, so you can make modifications as you see fit.
The security of the ring was one of the top development challenges, since you don't want the data getting accessed by an unauthorized person.
The NFC ring has 24 days remaining on Kickstarter, but it already exceeded its goal by at least £50,000. There are a few different videos on the Kickstarter page, but the one below is our favorite — it shows McLear demonstrating his phone unlocking skills.