Here is a quick and dirty teaser for my next goal: Building a RC car with LabDroid.

https://www.youtube.com/watch?v=DczLu7f4gTY

First step: Using the phone as a controller (GUI & rotation sensor)

LabDroid -> BT -> Arduino

Second step: Place the phone on the car and use the sensors to track the movements.

Tablet -> WIFI -> LabDroid -> USB -> Arduino