I run a small youth group at my church, and one of our annual events is a pine car derby race. Group leaders also get to participate, and this year I entered what I called the “CompuCar”.
Cars have to come in at under 5 oz. so putting wireless on board, components, and a battery, would have presented a major challenge if not for the Imp. Most of the wood was cut off the default brick to start, then various components were weighed until a good combination of visual fun was achieved. In the end, the configuration included a red and blue LED, and a BlinkM RGB LED. By default the lights behave like a police car - alternating red and blue (even the BlinkM).
Of course what fun would having an Imp on board be if there was no reason for the Internet connectivity? The lights on the car can be turned on/off remotely from a web page. Additionally the same web page controls the BlinkM state (on/off) and color. The web page is designed to reflect the iOS interface which most of the kids are familiar with using. Actions on the web page invoke XHR requests to Parse.com Cloud Code, which in turn POSTs the information to the Imp via HTTP In. This is done to (a) avoid running a server and (b) overcome browser cross-domain restrictions.
It’s not particularly impressive from an Imp standpoint, and even less impressive from an electronics standpoint (blink is the new hello world). The key was ultralight, power conscious, wireless, which would have been really hard to pull off with Arduino. And in the end, none of the kids believed that I built it myself.