The Gametrak system is a real 3DOF tracker. Well two actually, one for both hands.
Strings attached to your hands help the system measure
the distance and angles from the base item on the ground.
It then determines the x,y, and z position of both your hands.

They claim the latency is really low (0 actually), but I’ll wait to have my hands on one of these before assuming it’s true =)

Anyway this seems like a good toy to play with, I’ll try it =). At 30€, it may be very worth it !!