I have a rule that I'm not allowed to watch TV unless I'm doing exercise. (I don't have a "real" TV but watch DVDs and iTunes shows on my laptop and iPod, which helps control my watching.)
Normally this means watching shows while I'm on the elliptical at the gym, but even when I'm too pooped to go to the gym I have to do some handweights or jumping jacks or squats or situps during my show. I use the exercises from my Jillian tapes which I have learned pretty well now. It does make you feel a bit better about yourself than lying on the couch, especially if it is a really stupid show like [no I am too embarrassed even to tell you]. Or if it's a show with musical numbers you can count dancing to make the TV keep going.
[That sounds really lame now that I look at it, so I should add that there IS also stuff I do without the TV, like hiking.]
Squats or pushups against the kitchen counter while you are waiting for the coffee to be ready or the microwave to finish also count as exercise, so you if you do those you are not allowed to claim you are not motivated. And if you have started getting motivated, well then you don't have any excuse not to do just a little more then, do you?
Also, this chart may be helpful:
Should I Exercise Today by CrankyFitness.
As well as the
Motivation section generally of the CrankyFitness web page.