This weekend I went to Maker Faire. It has been held 2007, 2008 and 2009 in San Mateo. There was also a Maker Faire this year in Newcastle, UK. Austin, Texas has had Maker Faires in 2007 and 2008.
Maker Faire has everything from large Tesla coils and Flame exhibits to robotics and do it your self electronics to exhibits on spinning wool into yarn and making costumes. Maker Faire has some art projects that have been at Burning Man as well as groups such as Flaming Lotus Girls. There are several hands on things; as well as inexpensive classes and also children's activities. I spent most of the day Saturday there. It was a load of fun. Plus I bumped into many friends there.
I recommend Maker Faire.