I have an exercise bike in the basement in front of the TV.
When my Nascar races are on (which are typically 3 hrs long), I will get on my bike and ride at a moderate level, nothing too fast, something sustainable for the entire race. Then during the commercials, I will bike as fast as I can for those 1-2 mins. Over the course of the entire race, I can easily rack up 20 miles, and still get in some interval training while doing it!
(I've also done this during football games)