A team of five undergraduate students from the Worcester Polytechnic Institute has designed a prototype of what looks to be a cool 3D mouse that you wear on your finger like a ring. The MagicMouse works using ultrasound receivers that picks up sound waves emitted by the ring. You can move around in three axes at the moment, and the students are working on adding gestural functionality like mouse clicks as well. You can watch a video of the thing, if you can get the page to load. If you can’t, and you want to see some similar technology, watch this YouTube video, which demonstrates cursor control based on a user’s hand gestures in space — both hands — with no transmitting technology involved. Interesting.