User and programmer Theo Armour has published a nice demo of drawing in 3d with LEAP Motion. All you need is a browser, your hands and a leap motion.
Try out the demonstration:
http://jaanga.github.io/gestification/cookbook/draw-3d-objects/r1/draw-3d-objects.html
open hand moves your hand through the canvas, index finger draws. After you finished your artwork, you can rotate around the image with your mouse.
Check out Theo’s other demos: http://jaanga.github.io/gestification/