Well, if you could somehow get more energy out of it then maybe you'd be able to get it to preform some other tasks. Of course there aren't many tasks a coffee-table might preform, and there certainly aren't (enough? D:) mice in my house to keep it fed, but the idea is sound enough.

Perhaps some sort of fancy bird-feeder that eats squirrels...

Now, that bird-feeder idea has a market. I know some people with bird feeders and a deep, uncompromising hatred of squirrels.

What if it were charging your laptop/phone a la power mat?