>Cathy Pountney built a computer stand for her treadmill.
>
>>Now if they just hook up that treadmill to a generator you could be cutting your firms power bills while you work.
>>
>>http://news.bbc.co.uk/1/hi/health/6656631.stm

I can imagine reading or listening to music on a treadmill or exercise bike but not much else and even then not while really pushing it.