Hot because: Thanks to last year's An Inconvenient Truth, global warming was finally in the mainstream pop culture consciousness. Plus, the documentary won an Oscar for its director Davis Guggenheim, and it led to a Nobel Peace Prize for its star, Al Gore. Suddenly, contradicting what Kermit the Frog told us, being "green" was easy. The issue showed up prominently in all areas of film culture, from film festivals to Hollywood's pipeline, with another little doc -- featuring a huge Hollywood star -- situated somewhere in between. And it wasn't limited to what we see on the screen; it also trickled down to Hollywood life, becoming cool to even be "green" in your limo choices.

How to stay hot: Don't let this appear to be just another trend so much as an actually permanent new way of life. That said, don't let your critics and skeptics publicly point out how hypocritical you seem to be. Also, both documentarians and Hollywood needs to lay off saturating the market with too much "green"-centric stories -- and that means abandoning those Inconvenient Truth 2 plans. Otherwise, after awhile, the issue is just bound to get hokey again.

Next up: It's a HUGE deal!

Where did they rank?