WICHITA, Kan. (AP) — People at Wichita Oasis start showing up at around 10 a.m. on Sunday morning, drinking coffee and chatting before the music begins.

Once children are safely in the large playroom — complete with a chalk wall, a tent and plenty of toys — the adults and youths find their seats, ready for music and announcements.

But when the music starts, the songs aren't about Jesus. And when the speaker begins, he or she doesn't read a Bible verse.

Although Oasis follows a Sunday morning structure similar to many Christian churches, it calls itself a "community beyond belief," focused on a...