IRobot Sander

I love the iRobot collection.  If you haven't seen what they do you should take a look at: www.irobot.com. Anyway, I think one good idea would be to make an iRobot sander.  Then if you needed to refinish the deck you could just set it up before you leave for work or get ready to watch a football game and when your finished you've got a stainable surface.  This would be a good tool for hardwood flooring guys or people who refinish tables.

iRobot Shop Vac

They now have robot vacuums that go around your living room automatically and clean up.  I want one that has the power to sweep my garage and the profile to fit under my car.  Then at night the robot could sweep up the whole garage, even under the cars.  You would probably want to put the bot someplace visible so in the morning you could confirm it wasn't stuck under one of your tires.