In 7th grade I had a science teacher who was all about Earth Day. Obviously, he was environmentally conscious, something I didn't really appreciate then but very much appreciate now. He had a little saying that we had to say every day in his class: "Earth Day is every day, every day is Earth Day." For some reason, probably the sheer repetition of it, that has stuck with me. Doing eco-friendly activities one day a year is of no value unless it teaches you to do them every other day, too.
So, if you get a chance today, give the Earth a hug (or maybe recycle something). It's the only one we've got.