Better known as Chicago’s Singing Cabdriver, Ray St. Ray offers lucky riders the chance to hear him perform, a cappella or with CD accompaniment, an elaborate menu of self-penned songs. He’s a born extrovert, holding forth with songs and stories and showing an unusual proclivity for modeling funny hats, and he quickly takes charge of this documentary by Ryan Miera. As Ray’s grown daughter explains, he “needs a lot of attention and is good at getting it,” though she compares her own childhood to “being raised by a movie that’s playing.” Ray’s gimmick is a pretty small hook for a documentary feature, and the movie’s gradual slide into triviality is arrested only when his third ex-wife reveals that he was once a high-ranking “OT” (Operating Thetan) in the Church of Scientology. Ray smoothly fields Miera’s questions about this, claiming that the church sided with his wife when she divorced him, but it’s only enough of a story to make you realize you’re not getting the whole thing.