I liked Exit Through the Gift Shop well enough. Its bad-boy, Euro-trash pranksters bite their thumbs at the art-world that feeds them by playfully manufacturing a hoax-star doppleganger forger from thin air, then selling his misbegotten wares for millions: gotcha! But really, guys, Orson Welles did it all before, with better craft, crazier detours, and actual genius. F for Fake (1973), also a film about (male) authorship, authenticity, and the value of art--as warranted (or not) by modernist masters like Howard Hughes, Pablo Picasso, and Orson Welles--runs intellectual, artistic, and charlatan circles around the pomo school-boy thrills of wheat-pasting and the endless whirlpool of appropriation.
See F is for Fake and the rest of my thoughts on my blog.