"Internet nexus of cultural Judaism" — Examiner.com
I always figured Frink (and his father, guessing from the fact that he named his son after him) were ethnically Jewish but atheist and non-practicing like many scientists. The only episode I've ever seen where Frink was in church was the LEGO episode, Brick Like Me, which is non-canon as far as I'm concerned. I can't imagine Frink being a Christian.
Frink in church