One of the best single exercise you can do is the PUSHUP. It will work just about all the major muscles from the arms, shoulder, chest, stomach, legs, you name it. You can do them during commercials
.... Fast and simple. Start with however many you can do without straining yourself...then wait three minutes and do another set...then do one more set. Don't worry if you can't match each set, just go till you are starting to strain. In the very beginning I could only do 10 or so at a time, but within a few weeks, I was pulling 35 at a pop. You will quickly see a progression that you can measure and that will keep you going.
out.