Big blockbusters like Avatar and this Summer’s Robin Hood are all about making cash. Obscene amounts of cash. Filthy amounts of cash.

But today’s debt and carbon filled world has made the beneficiaries of these money-magnet films think about what to do with the tens and hundreds of millions of dollars they generate.

Avatar’s James Cameron and Sigourney Weaver were in São Paulo to plant the first tree as part of a global partnership to plant one million trees worldwide – an initiative between Fox and Earth Day Network to promo the Avatar DVD. Cameron planted the pau-brasil – a native Brazilian tree – which is a powerful symbol of recouperation of the forests in that country and a species that is 99% extinct.

Seems he’s not just concerned with Pandora. I guess those people who spotted the subtle environmental message in Avatar were right all along. But it’s not just Avatar.

Universal has announced the launch of its "Robin Hood: Lionhearts" program, a cause-based initiative designed to reward those who “dedicate their time to changing the world”. The scheme aims embody the legendary Robin Hood message through peer sharing and social networking.

It’s about Lionhearts, defined as “people who make a positive impact in society via their participation in a cause or charity.” Three Lionhearts will win a Grand Award and receive $5,000 each, in addition to $5,000 to share with a cause of their choice. Ten Lionhearts will win a First Award and receive $500 each, in addition to $500 to share with a cause of their choice. Lionhearts will be featured through an online profile along with their chosen cause. Universal is working with not-for-profits United Way, City Year and Robin Hood, to identify Lionhearts in their respective organizations.

You could read into the obvious PR thinking behind this. In both cases, the “cause” publicises the movie heavily. But the benefit on the other side mean this is undoubtedly to be applauded.

It’s only right that when blockbusters are shoving a moral message down our throats, they should promote that message actively in the real world. This particularly applies to those that count their box office take in billions. That means you Avatar.

We’d love to see this sort of charity from every blockbuster. Spidey 4 could fund the protection of rare, urrr, spiders. Or something…