Two of my favorite toys right now are my Lego Mindstorms set and my Android phone. And thanks to the Bluetooth protocol I've found a way to combine them. Behold!
Since the video is quite blurry, here's a better view of the application's interface:
The third control scheme (not pictured), which I like to call the tank mode, allows you to control each motor separately and works best if your phone has true multitouch support (not just pinch-to-zoom).
Now I'm not saying my application is very unique, there are at least two others on the Android Market that do the same, including an official one from Lego. But hey, it's mine!
If you'd like to try it, below is a QR code that you can scan from your phone (or if you're reading this on your phone, just tap the code). And here's the application's AppBrain page. (It's free of course.)
Finally if you'd like to see the source code, it's over here at Google Code.