Copenhagen Bike Wheel!
The Copenhagen Wheel replaces your existing rear bicycle wheel to give your bike power assist and regenerative braking. It’s got built-in wifi, making it all tunable via a real time iPhone app. There’s even an SDK for developers.
I love great bike tech. This is a little pricy at $799, but I can see the value for commuters who face a lot of hills on their rides. You can preorder the Copenhagen Wheel from superpedestrian.com. Watch the video to get the whole concept.