It's called runScribe, and it analyses your gait as you run to give you incredibly detailed feedback on your technique. Just clip it onto the back of your running shoe, and off you go.
Its 9-axis sensor means it can make thousands of calculations for every stride, and report on 13 detailed kinematic metrics. This means an unprecedented amount of feedback, leading to better technique, faster times, and fewer injuries.
Start using it, and it'll give you a runScore, which measures how intense your run was. This lets you compare it with previous runs, so you can see which terrain is better for you, environmental conditions, and so on.
You can also use it to measure the different kinematics in different running shoes, so you can see which actually help you perform better.
Data is beamed over Bluetooth to your phone, but you don't need to take your mobile out with you. runScribe can store the data on its flash memory, and then sync with your mobile when you get home. It works with Android and iOS devices, and you can log on to the website to see your stats.
As well as basic running, runScribe can help with events like the sprint, long jump and hurdles.
It's already right near its funding goal of $50,000 on Kickstarter, so it looks like this will go into production. The first units are expected to ship in November, just in time for some winter running.