Stunt kites! A former empegger (Rob Vreeland) was a champion trick flyer. If you think that display you saw was amazing, you should see a group fly acrobatic show... where you have 4 guys flying stacks like that and doing a show similar to a Blue Angels precision flight or a hot tricks demonstration where they can make the kite flip flop, spin, fade... and all kinds of other craziness. I'll see if I can dig up some videos.

OH... then there's Revolution kites. Quad line controls... like a puppet in the sky!
http://www.revkites.com

You could also do fun stuff like this with kites:
http://www.brett-schulz.com/albums/album11/loren07.mov

OH... and Matt's link to Prism is a good place to get started... they make some awesome kites.