what the others said about training sessions is good. You could mix in regular precision obedience (heel, sit, stay, recall) with teaching tricks using the clicker. Lots of ideas on the web but the fastest tricks come from what the dog will offer up on it's own. Now if only I could get Frosty to do commando crawl on her own and not when she's trying to sneak somewhere with the lead on.
Also tug of war and wrestling are good in a smaller space where running is hard. I imagine with kennel cough, the exercise needs to be a little bit often, rather than a lot all at once.