Secret Agent Vacuum!
So I have to admit, I always thought roombas (robot vacuum cleaners to those unfamiliar) were in the pointless-but-harmless category. I mean, as long as your not doing anything illegal or immoral, who am I to object to how you clean your house? After reading the following however, I decided they were not so harmless.
In short, roombas collect and record information about the layout of your house, and they can be connected to the internet. Anyone besides me find that a little scary?