Got Son a hoverdisk for his birthday. It cost too much, but then trendy things usually do.
But from a geek perspective, it's kinda neat. It has a battery pack driving a propeller, which points downward. The body is styrofoam, and due to the "equal but opposite reaction" thing, rotates in the opposite direction of the prop. But the body itself has blades, so that its rotation adds more lift.
The controller has a sticker on it labelled "30MHz", and claims to work at a range of 60M. It's actually a variable speed control, so that you can, with practise, get the thing to land gently, although it's survived fairly well at my and Son's hands.
And the charger adapter has two boxes, which is odd (and IMO poor/cheap design). One looks to be a standard transformer coming from the wall, and the other a featherweight box that sits between the transformer and the disk. The "other" has a switch and an LED; when plugged in a charging, the LED blinks, and when the blinking stops, you're ready to fly again, the whole process taking about 3-5 minutes. One oddity/nicety about the charging process is that it won't start charging until the disk is sufficiently drained.
Draining the disk takes not too long, but long enough to have some fun. But about 1/3 to 1/2 of the flying time has the disk not able to clear even Son's head. The last 1/4 of the charge, though, shows ground effect. The disk will lift off maybe 3-5 inches of the ground, and hover there. If you launch it by hand, it'll settle slowly to that point, then continue to hover. Nifty stuff.
Of course, this'll be a fun toy for the next week or two, then collect dust, unless I can find something else interesting to do with it. (Suggestions welcome...)