I'm a programmer and I have a strong desire to create a big website that will be free and useful as Wikipedia. Any Ideas?

I'm an experienced programmer and I have a strong desire to start online project that will be free and good for all people as Wikipedia. Any Ideas? Currently I'm thinking about some science-oriented community. All science is controlled by world's governments because science needs a lot of money. And how many new knowledge we get from that? Nothing. All new science explorations are hidden from us.

We have seen how easily Wikipedia collected millions of dollars from donations in just 2 months. We can do our own science researches, we don't need government "help" for that.

Any other ideas for new projects will be highly appreciated.