L-bot!
https://www.youtube.com/watch?v=c4nsFmmZPmo
The most magnificent robot I've had the pleasure of working on BY FAR. The scoring mechanism is a cardboard tube attached to a piston. With a sweet 2 wheel drive and 7 caster wheels, it glides effortlessly across the arena! And how could anyone forget the 60lb steel plates zip tied to a piston on the side of the robot!