Sure thing! This video here is a good example of what R.O.B. can do.
In the video, you might notice that R.O.B. starts to move when its eyes detect a certain kind of flash on the screen (much like the NES Zapper works when you play Duck Hunt). In this case, R.O.B. picks up and spins a gyro (the top-like object) and places it on a pad, which then presses a button on the 2nd-player's NES pad. In essence, it's like having an automated partner that reacts to what you do in the game.
In a hypothetical game design, you might issue commands to R.O.B., and it could then press the A or B button on the other controller to affect the game you're playing on the T.V.
And as you can see in the video, R.O.B. takes a while to move and pick up objects, so you'll have to factor that into your design as well.
Hopefully this clears things up! Let me know if I can help any further.
Edit: I've gone ahead and added this information to the main challenge page for reference.