The MakerFaire is coming next week to the San Mateo Fairgrounds about 10 miles south of San Francisco. Many strange devices as well as straight-up model engines will be in exhibition. We have had steam-powered bicycles, fire spewing calliopes and robot competitions. The variety (and strangeness) of the projects reflect the variety and strangeness of the San Francisco population.
http://makerfaire.com/It is not as sedate as the Model Engineering Exhibition in England that I was lucky enough to attend several times.
Both events are filled with people who didn't realise that what they wanted to build was not possible/practical, so they went ahead and did it.

-Dick