A bunch of different folk are doing BarCamps* on a Green theme. This GreenCamps page lists the ones I could find, though I haven’t had time to organize the page.
*A Barcamp is also known as an unconference – a very ad hoc conference. usually they are mostly on tech subjects. Think how the conferences you’ve been to have often been more notable for the conversations that have happened spontaneously, rather than the main talks. A BarCamp has a lot more of the informal stuff, and short talks can be given by anyone, at short notice. You can choose which talks to go to, or just do your own thing.