It's great concept, especially if you are goal-oriented. I use a similar technique for household chores: I'll watch a show that I like in the afternoon, but during the the commercial breaks, I wash dishes, clean the bathroom, or whatever. I'm always impressed with how much I get done.
Yeah, it seems to work really well for doing household chores during commercial breaks, especially since we dread doing them despite most of them only taking about 10 minutes. (If it takes more than ten minutes to unload the dishwasher, you've got a problem!) Plus you get a nice little reward for your effort!