Charel has invited Joe Grand to be the keynote.

Joe Grand is an electrical engineer, hardware hacker, and daddy. He has been involved in electronics since the age of seven and specializes in the invention and design of consumer devices and modules for electronics hobbyists. He runs product development firm Grand Idea Studio http://www.grandideastudio.com and is on the technical advisory board of MAKE Magazine. Joe was a member of the legendary hacker collective L0pht Heavy Industries and was a co-host of Prototype This, an engineering entertainment show on Discovery Channel that followed the real life design process of a unique prototype every episode.

Caught this video online, and think it very much has a maker fair sort of vibe to it. although probably would not be able to do such a build in civic plaza.. due to noise ordinances.

Although as devices go, we have managed to have smaller (like 2.5' long 4" ABS drain pipe made carbide cannons) certified as ok, by the forest service, because they did not meet the definition of a fire arm, or a firework. The closest thing they could find was that they were an internal combustion chamber, or a noise maker.

Sadly the noise is pretty loud, so we would likely need some sort of waver/permit/zoning clearance. which might be more trouble than its worth.

But enjoy the video!
http://youtu.be/fRfuo-LfgUk