Once people get into their heads that maybe the personal automobile is not really such a good idea -- in other words, after they have moved beyond the biodiesel/electric car phase, as if the only problem with the personal automobile is the fuel it uses -- they usually fixate on bicycles.
I say "fixate" because this often becomes an eco-fetish like so many other such things, as if more bicycles were better, and if you could just get enough bicycles in one place, you could "save the world."
The focus on bicycles is typically because, in the mind of this person,they still assume that they would be living in Suburban Hell, or perhaps some earlier variant of Suburban Hell (the 19th Century Hypertrophic Small Town America). Of course, if you are stuck in Suburban Hell, with its endless expanses of NoPlace and absurdly long distances between Places, then you would want a bicycle at the very least.
I found out through EL that San Jose has its own version of Critical Mass: San José Bike Party (MySpace).
SFGate article on the San Jose Bike Party
San Francisco Bicycle Coalition
SF Critical Mass
