That's awesome. I remember back when I was younger, I had this tractor-trailer Lego Technic set that had a crane on the back of it. It had a fully-working pneumatic pump system that had actuators and all sorts of stuff to make the crane on the back of the rig fully functional. Here's a pic:
<img src="http://www.fifth-r.com/cssoh1/supplies/pneu_sets/8868set37-320crp.jpg">
That thing was so awesome. I still have about half the pieces to it. It's half-assembled right now in my parent's basement. I would kill to be able to order the entire set again and put it back together.