I'm also a European who lived in Cali for over 10 years. I used to not care about the community in the beginning, but lately I've been really enjoying doing community work, helping and donating to the local schools. I feel more home here now than I ever felt "back home".
I guess America changes you.
If I had the means, I would be happy to donate to local schools. I believe in giving back to society. Besides, I am a rather social person. I just don't like to be coerced into doing things I don't like... like having to put up with neighbors I don't like just because they're part of my "community" and I need to be good to "my community" so they will reciprocate. I think that my money, my attention and my time should be invested in those who are worthy, not necessarily in those who happen to live in the same street I happen to live in, that's all.