My DVR grabbed this off the Sundance channel recently, it was exec-produced by the recently departed Don Hewitt of "60 minutes" fame, and it has a bit of the editorial feel of an extended piece from that show. Very fun and interesting look at the collective hallucination and kingdom of subjective opinion that is the "legitimate" art world.
Summary: old truck-driving grandma finds a spattered painting at a thrift store for five bucks, it might be a real Pollock painting worth 20 million, but nobody in the art critic world will acknowledge it as such, as long as the old lady owns it. A forensic expert is brought in to try and confirm the painting which is unsigned and has no provenance records attached to it. All manner of art "experts" look at the painting and all dismiss it as fake.
Unlike too many docs of this sort, this one DOES have a fairly conclusive end to it, you'll have to see the movie to know which way it went.