Beaming Vacuum Cleaner
You might have heard of the fact that "beaming" (like in "Star Trek") has been discovered for very small particles?
Well, the logical application would be to invent a vacuum cleaner using this feature. You could have a tiny divice (without dragging behind you the huge machine that always gets stuck somewhere between your furniture), and in doesn't matter if the technology isn't perfect yet or still involves some risks (just as in "The Fly"), because if the molecules of the dirt you are trying to remove get mixed up in some way, no one cares.
Reward: A free beaming vacuum cleaner.