Times-Up! - Environmental group in New York City with accent on bicycling and pedestrian rights and activities. - http://www.times-up.org/
Rainforest Action Network - Works to protect the Earth's rainforests and support the rights of their inhabitants through education, grassroots organizing, and non-violent direct action. - http://www.ran.org/
The Ruckus Society - Tree climbing, banner hanging and all manner of Direct Action Training. Committed to making other environmental activists and their campaigns more effective. - http://www.ruckus.org/