What would be a good movie to show during earth week?

I run an environmental group at my college and we always show a movie during earth week. In past we've shown The Rescuers Down Under, Happy Feet, Little Shop of Horrors, An Inconvenient Truth, and last year we showed Wall-E. Now we are out of ideas. I was thinking Soylent Green might be fun, but that's the only idea I had. It doesn't need to be a kids movie, just a movie people will actually come to see. I'd really really REALLY appreciate any suggestions. Thanks all. Oh and I know Ferngully would be perfect; but, we've been trying to get that one for years but haven't had any luck, so please don't suggest it.