Twenty sing-along or listen-to songs about the environment. Great addition to a unit on the environment or for earth day. Teachers (me included) have been using these songs in classrooms for twenty years and many teachers have used them year after year. I've tried to create songs that are fun and not preachy - leaving it to the classroom teacher to use them as a springboard to discussion.
Download the Sixteen Bears track for free on this site. You can also preview a number of the songs on http://penultimateplustwo.com/childrens-music/carnival-of-life. If you're an iTunes user, the album is available there and there is also an Accompanyment Only version of the album (No vocals) on my store Penultimate Plus Two.