HowTo: Build a Robot That Will Clean Your House
Cheaper (and perhaps cuter) than a maid, the simple scrub bot is easy and cheap to make:
"This state of the art cleaning robot is great at polishing floors and shining glass tables (provided that you soap it up first). It also disperses small particulates evenly across your floor in such a manner that your home may look cleaner than it actually is."
See it in action below; click through for detailed instructions on how to do-it-yourself.