Just a random idea.
During commercial breaks while watching TV, when they start do this:
push ups to failure
20 reverse crunches
30-60 sec plank
15-20 mountain climbers
Then if the commercials are still going start over at the push ups. Stop when your show is back on.
And no rest in between each exercise. Only rest if you complete the whole small circuit and about to go at it again.
Have fun :)