This is an Egely wheel. It is a very simple device, basically just a plastic disc resting on a metal spindle, so it turns very easily. Light drafts can already make it turn. The surprising thing is, that it almost always turns and in a specific direction, when you put the inside of your hand around it without actually touching it (as in the photo below). This works with nearly every person. It appears as if there is some force coming from your hand that is causing it to turn. The possibility of air currents should be excluded of course by being inside a closed room.