Mine is a really weird sort of exercise... the vast majority of my house is either hardwood flooring or tiles, but the stairs are carpeted (low pile, worn down further by yeaaars of trampling). Mocha hates hardwood and only likes places with traction, so what I do is carry him down to the bottom step and taught him how to hop up the stairs. It took some urging and bum-pushing at first because he was both skittish and confused, but he got the hang of it pretty quickly and soon learned to bound up the steps all the way up to the one just below our second floor-- because due to the hardwood flooring, he can't really rest his front paws on it for leverage since he slips easily. At that point, I just pick him up and go back down the stairs for another round or two lol. It's no agility course, but it does at least force him to exercise a little more than his usual binkies!