PumpTire has developed the world's first self-inflating bike tire, which actually takes in air and inflates to ideal pressure as you ride. This won't keep you from ever getting a flat or anything, but it could spare you a lot of tedious adjusting and checking of tire pressure.
The company is raising money on Kickstarter to make the tires commercially available. You can pledge $45 to get one self-inflating tire, plus a pressure control valve and an inner tube, or $75 for two — not too bad as long as they last a reasonably long time.
