What are good volunteering programs?

Good volunteering programs for teens in the US (preferably)?

• I'm sixteen, and I want to help in the US (I live in California). Anyone know good programs? I'd prefer something hands on, like building houses or schools, but anything would be much appreciated. And this is all speculative so if you had a good experience working internationally then feel free to suggest that, too. I'm not confining it to the US, but it is cheaper that way.

• Answer:

  Habitat for Humanity is one of the most wide-spread, not-for-profit home-building programs. Or another very rewarding thing to do for volunteer work is helping at a humane society. Literally hundreds of thousands of animals are euthanized each year in America because shelters don't have enough help and resources to quickly and effectively find permanent homes for their animals, so helping there could make a big impact.