Ariane Sherine, creator of the Atheist Bus Campaign, and editor of The Atheist's Guide to Christmas. She gave the first official Humanist "Thought for the Day" on Radio 4 in 2004 (apparently Dawkins had given an unofficial thought in 2002).
She's also comedy writer and journalist. According to Wikipedia, her father is UU, and her mother is Parsi Zoroastrian, although neither practice.
I'm a believer - in plastering buses with atheist slogans:
Although not atheists, my family have been broadly supportive of the campaign. My 83-year-old Zoroastrian grandmother sewed advert covers for the launch and told me that my devout Jehovah’s Witness great-aunt saw me on BBC News. “What did she say?” I asked nervously. “She said it was very nice,” my grandmother replied.