Personally, I think Josh Rachlis (as Enviroman) and Jackie Eco, mentioned on MNN are hilarious. Josh is very clever in the way he fashions an eco coolness about himself, using the concept of eco heroism and being cute and quirky. Environmentalists have a habit of taking themselves a little too seriously, and Josh turns this on its (or should I say, his very own aerodynamic) head!
Jackie Eco (pictured above) is much more satirical and does some fabulous impersonations (Hilary Clinton, Cher). Apparently she has been campaigning on environmental issues since a youngster.
As I said in my comment on MNN, hail to thee eco-comedians and comediennes - and keep the eco comedy torch alive.