[GRST]

How about... Rack n' Roll with a Tetra!

Instead of the Rack, you have a gigantic tetra which you somehow score on. your robot can lock onto IR targets (seeing the success with which we used the green lights, those are probably out).

Perhaps there is also an element of Raising the Bar, where you have to hang on something or get over something- if you get over the Tetra you get extra points? There might be some device which the robot would have to use to get over- maybe an element found on Copley Square?