Levitating screw magnet trick
If your house happens to contain long coil-like things and bar magnets, then you can levitate a screw just by using common household items.
That's according to this video.
Presumably the screw hangs there spinning like some crazed metal transcendentalist because the juice of the lemon also sends juice along the wire which develops and electrical field precisely aligned to the grooves in the screw caused by....
Whatever. Who knows how this thing works?