For those in the Bay Area, I would encourage you to attend Maker Faire. May 3-4 at the San Mateo Fairgrounds -- and not to be missed!
I went last year and vowed next time to go both days. It's huge and full of really, really fascinatng exhibits and brilliant ideas. Lots of free stuff.
What is it? It's the heart and soul of do-it-yourself. Hundreds of people who make stuff and love what they do so much that they stand for 12-hour days waiting for people to come by and gawk at their magic. Organizations and museums that have created hands-on demos you can play with.
If you like metal and fire, gears and gadgets, Legos and things that move, honk, squirt, squeak, spark, and belch, you have to go.