
NXBike got an upgrade. Young humanoid added an ultrasonic sensor so it could avoid obstacles, and a better second-NXT controller so it could be remotely operated. You can find step-by-step instructions on this web page:
http://mindstorms.lego.com/nxtlog/ProjectDisplay.aspx?id=aae4e4ef-566d-4647-9870-e018b0124869