From my Jewish friends I learn that it is possible to be both a religion and an ethnic group at the same time. Some things about that seem paradoxical, but that doesn't stop it from being true. Just because you've become a Buddhist-- or a secular humanist, or a neopagan priestess-- doesn't mean you've stopped being a Jew.
The Jewish people think of themselves as a tribe. A tribe is a people who are bound together by history, by culture, and by a network of community relationships. Formal religion may be a strong part of that-- but it is not necessarily a defining part.
I think the UUs can learn a lot from the Jews about how to think of ourselves as a people.
Jews are a people who are both white and not white at the same time. I think that this is also true of UUs. It's an important thing to talk about, to learn about.
Another important thing I learned from Jews is that one aspect of cultural difference is about gender. In Jewish culture (Chinese culture too), the woman was the one who is supposed to go out into the marketplace, to be loud and aggressive. The man is supposed to be a gentlemen scholar, a senstive poetic type. Standard American butch/femme just doesn't apply in the same way.
It is my perception that in UU culture, definitely in our current generation of UU young adults, gender roles and experiences are very different than in the dominant culture. I'd say in some ways they are reversed.