No spill cup holder (gimbal)

These things work amazingly well. As long as you don't bump the hanging tray, you could literally jog with this and not spill a drop.
I've always wanted one, so I made myself one. We have some big 130mm coffee cups, so I made it large enough to accomodate them.
Even with a small tea-cup filled to the brim sitting on this thing, you can walk around carelessly and the cup never slides, and the fluid never spills.
http://www.youtube.com/watch?v=Fo9SajeU2b4

Update: If you put a glass