Well, the practicality of it might be a bit exaggerated, but its by far more practical than an 8 story tall mech standing in your back yard as you build it. Basically this guy gave his computer chair working legs.
It uses a Basic Stamp II microcontroller to run just about everything. The rest is a couple motors for forward and reverse motion, a couple pneumatic cylinders for up and down motion, an air compressor, and a power supply.
The best part though has to be the IR sensor that allows the guy to use his remote control watch to control the seat. Its apparently a fairly expensive project, but not too terribly pricey, it appears to still need to be plugged in, but making it battery powered with it lasting any respectable length of time might be the most expensive part of such a project. It is kind of nice to see someone do something like this and make it look simple, I think if an even moderately mechanical person with some decent soldering skills got a parts list they could put the hardware portion together, the programming of the controller would take the most skill.
DIY’er creates homegrown mini mech [via engadget]