Just wanted to report that for the first time in my life I've been using Mathematica to do actual real-time measurements in an experiment that I'm currently performing. Jay!
I'm using a Wii balance board (from the Wii fit game) to measure changes in my subjects' centre of gravity.
The Wii Balance Board connects through bluetooth to my laptop. Using the programs GlovePIE (http://carl.kenner.googlepages.com/ glovepie_download) and PPJoy (http://www.geocities.com/deonvdw/Docs/ PPJoyMain.htm) and a small script I wrote for GlovePIE this is converted to a virtual Windows joystick X,Y values which can be read directly and easily using Mathematica's ControllerState function.
This gets me about 400 samples per second. A real-time plot of the user's motions reduces it to about 20 Hz. Still not bad at all, and very useful. Works for the Wiimote (acceleration sensors!) as well.