Photos: Earth Day memes strike back!

How do you commemorate Earth Day? By planting a tree? Cleaning up around a park? Biking to work instead of driving your car? Kissing the ground your beloved walks on?

Whatever your celebration of choice, we suggest you supplement it with a little laughter courtesy of the following Earth Day-centric memes, which prove that even environmentalism can be funny.

Check out the complete collection below -- and happy Earth Day!