Earth Day is just a month away, on April 22, 2008. There will be plenty of opportunities for you to get involved in any way you can. If you don't want to volunteer, you can always plant a tree, or at the very least, ride a bike!
A cool blog I just discovered is Baltimore Spokes, which -- as the name implies -- is focused on bicycling in Baltimore. I must admit, I don't do much riding up and down Harford Road, but I have seen some brave souls attempting to maneuver the traffic. And really, there's no reason why our neighborhood shouldn't be more bike-friendly.
As gas prices continue to rise, it might be time to get the 'ol Hello Kitty bike out of the basement and take her for a spin again.