As a cofounder of Google, Sergey Brin has already done lots of very good things for the world on a macro scale.

He's given us a great technology that makes the Internet usable, created a company that provides jobs for tens of thousands of people, and donated millions to various charities. He's investing in genetic cures for diseases and space exploration, too.

But one of the coolest, warmest things he's doing with his money is on a much smaller scale.

According to the WSJ's Amir Efrati, Brin has created a small real estate holding firm called Passerelle Investment Company. With it, Brin is buying up downtown property in Los Altos, Calif., a small Silicon Valley town near where he lives, and is renting it out at below-market rates to stores he thinks families in the community need: a children's bookstore, a children's playspace, and a child-friendly coffee shop.

I can already hear people complaining about this post: "Great, a rich guy is making a rich town nicer to live in."

But Brin is doing a lot of other stuff for the world, and he doesn't have to be investing in his community like this at all, and it's just really cool that he is.

No wonder so many Googlers are rushing to work for Google X, Brin's secret projects division at the company.