Streetbank and Make Wealth History

Here's a couple of good websites I've just found - one a brilliantly simple idea to help neighbours and neighbourhoods, to help real community building in a friendly and useful way- successfully trialled in West London and went nationwide in April 2010. Is there anything like this in the USA I wonder?:
Streetbank

The second is a Christian site, an exploration of sustainable living in the real world.
Make Wealth History Because the earth can't afford our lifestyle.

Any others on the same lines I should know of? I'd like to hear.