"Sister Mary..." puts Diane Keaton in the title role, on stage at a Catholic Christmas pageant, where she...um, well, mostly lectures about Catholicism...blaa, blaa, blaa...cut to the chase...bottom line; this movie pokes spoofy fun at the Catholic religion which I, not being Catholic, thoroughly enjoyed. The film is a tongue-in-cheek, not-to-be-taken-seriously blatant lampooning of Catholic dogma mixed with silliness, nonsense, and borderline slap stick. Not likely to receive rave reviews, this little flick offers fun for those who don't mind a little blaspheme...okay, a lot of blaspheme with their humor.