This is the first Arduino bot ever built from geekionizado and was recently posted in LMR. This bot with the happy face, can detect obstacles with it's ultrasonic detectors in his eyes. Then, it turns to the direction where no obstacle was detected, and moves towards this direction. It uses a Tamiya dual motor gearbox controlled by a L293D H-bridge for the wheels, and a turnigy 9g servo to turn its head. Check out this link for more details.