cute. what's the behavior it's following when it encounters something?
for suggestions, what about finding a path to a specific spot in a room full of obstacles; Following a wall; or solving a simple maze.
There's a robot called makey with similar structure and some cute behaviours. It will follow a moving object for example.
Just a thought on coding for this kind of robot. Instead of a bunch of different routines for forward, backward and turns, consider using something like "drive(int l, int r)" l and r are pwm values for the left and right motors with positive and negative for forward and reverse.
Just a thought. I saw this in someones code and it simplified mine a lot.