If you are still interested in sending the to Africa (Namibia) this place does that.
http://www.bicycles-for-humanity.org...Contact_Us.php

They have sent a shipping crate of bikes there and are still active. Not sure when their next shipment is. There may be a bikes for humanity closer to you. There is also the recyclery in San Rafael.

Like DG says, the Crucible does neat stuff with local kids. They are also having their Holiday art sale and open house this weekend. A good excuse to check the place out and drop off the chains.