In celebration of Earth Day, The Sak’s eco-extension, Sakroots, is hosting a celebrity bag auction supporting The Nature Conservancy’s Plant a Billion Trees campaign. For each dollar contributed to the initiative, one tree will be planted. Starting on the 8th and running to the 22nd, a celebrity autographed sakroots Pax Eco Weekender will be up for grabs, signed by Robin Wright Penn, Rosie Perez, Blair Underwood, Justine Bateman, Jessica Alba, Alec Baldwin, Sandra Oh and Mena Suvari.

Sakroots Pax Eco Tote is made of a jute/cotton blend canvas and has 100% natural cotton handles. It features The Sak’s signature peace print symbolizing the brands’ “happy & free” philosophy with artwork created by Paris-born graffiti artist. To hit the auction, jump here!

Most recently, Robin Wright Penn has joined the green mothers of Hollywood (reality television show, anybody?) by committing to lead a more eco-friendly lifestyle. How oh how, you ask? Easy! Penn is taking the EcoMom Challenge — a program from the baby makers at the EcoMom Alliance.

The EcoMom Challenge lays out ten easy-to-follow steps — from re-thinking your laundry plan to shopping local — on how YOU can help make a more sustainable future for those adorable little ankle-biters in your life. Robin said: “I get way too overwhelmed if I focus on the larger global picture. But as a mom, I can do these small things on the EcoMom Alliance list and know I’m doing something positive and protective.”

If you’re a mom (or dad, or neither) and want to get a few easy tips on making the world a more sustainable place for the kids of the future, visit EcoMomAlliance.org and take the EcoMom Challenge. Come on, all the cool moms are doing it!