How about these for events:

Bath tub stopper hockey (you can substitute milk rings or bottle caps for the stopper)
Bath tub paw skating. Is real fun with ceramic coated tubs.

Best Box as a bed. Requirements are 1) no space left over and 2) no more than 10% of body overhang (0% is preferable)

Laser Bug chase - that cat must chase and not give up. Longest time requirements