Anyone who's ever emptied a pool or stolen petrol from a car's tank knows how a syphon works, but that doesn't make this 3D printed Wave toy seem any less magical. Seeing it in action you'd assume there was some kind of sorcery involved here, as one side of the Wave draws liquid to the other until both glasses have the exact same amount of liquid. But it's just well known scientific principles at work.
You can recreate the same effect with a short length of hose, but this £15 (shipping included) 3D printed nylon tube introduces enough mystery to make the whole process seem impossible. It's a little late to get one to impress the children at the kiddie table for holiday meals, but your dim-witted friends should walk away suitably confused and awed. [Shapeways via Notcot]