I just finished a new DIY tutorial on building a motion (sometimes called kinetic) controller for any of the Alexmos-based gimbals, like the Pilotfly FunnyGo - you can check it out here:
It's pretty awesome, of course I'm a bit biased.
You can build it for under $50, although it definitely is a more complicated build than my last controller... The way it works is it has a gyroscope/accelerometer built into it (actually, the same one used in the gimbal), and it transmits the orientation data in realtime via bluetooth to the gimbal. So you just hold this like you want the camera to be positioned, and that's it! It works really well when combining it with someone else moving around with the gimbal, and playing with the different modes. It really allows you to create some smooth camera movements, and is VERY easy to track things like moving cars, people, or whatever. Hopefully a couple people take a crack at building them, and shoot some cool video using them - either way, check out the video and let me know what you think! 
It's pretty awesome, of course I'm a bit biased.