Zumo projects

I bought a zumo assembled kit and i practiced the following projects

  1. line following
  2. maze solving
  3. edge detection
  4. collision detection
  5. obstacle avoidance
    and almost all the examples available in library. could anyone suggest me some more challenging tasks that can be accomplished by the kit with an ultrasonic sensor…

How about: Try to find a lit candle, and put it out. You may need some IR sensor and fan (or squirt gun) to make that work.