The Laboratory of Neuro Imaging at UCLA has a collection of super cool stills and quicktime movies of the brain. They are either composited from actual measurements or illustrative models. At the more entertaining end is a Cortical Journey with serious Matrix envy as the movie runs from an outside view of the brain through evermore detailed sections until you find yourself in a mesh of green neurons and finally descend along a dendrite into the core (soma) of a neuron and pass along with a merry group of neurotransmitters across the Axon Hillock down an axon towards a synapse.
It may be just for show, but as such it's an awesome animation.