I think "Paprika," a Japanese anime film from Satoshi Kon, would have fared better in my mind had it been released a decade or so ago:
I'm familiar with most of Satoshi Kon's work (including the seminal psychological thriller "Perfect Blue"), and in "Paprika," he ambles along the rather well-trodden paths of solipsism and science fiction. You've seen this kind of reality-bending before - from the mainstream ("The Matrix") to the less-mainstream ("Eternal Sunshine of the Spotless Mind") to the fairly obscure (eXistenZ). This familiarity is probably the movie's biggest weakness (along with some murky character motivations).
Atsuko Chiba is a psychotherapy researcher who uses a top-secret device that allows her to share in other people's dreams. Unfortunately, some of the devices are missing, and soon the research staff's dreams are invaded by the thief. The tale spins pleasantly out of control as Atsuko (in the guise of Paprika, her dream avatar) and her colleagues try to contain the damage. Predictably, though, reality itself gets called into question. What is real? What is a dream?
As might be expected from Studio Madhouse, the animation is excellent, with some extremely detailed CGI to go along with the hand-drawn stuff. There are some incredible setpieces in the movie, including the strangely sinister parade that soon carries some hefty symbolic weight. I could have used more character development (Chiba is mostly a cipher, and there's a final change in her relationship with one of her friends that is a bit forced), but overall, it's worth watching.