When you have about 50 minutes on your hands, meet Kim Peek, the real life Rainman (which is to say that the movie was loosely based on his life):
Part 1/5: http://www.youtube.com/watch?v=k2T45r5G3kA
Part 2/5: http://www.youtube.com/watch?v=NJjAbs-3kc8
Part 3/5: http://www.youtube.com/watch?v=Auufbu_ZdDI
Part 4/5: http://www.youtube.com/watch?v=vRPxMDj33S4
Part 5/5: http://www.youtube.com/watch?v=a1aA5osvYgY
It would have been interesting to "know" Kim before Rainman, which seems to have had a profoundly positive impact on his self image and socialization skills during the intervening years. I'd imagine that Dustin Hoffman's portrayal would seem much more spot on if we were afforded a glimpse of what he was able to observe at that time.
Edit: I'm just learning about Kim Peek, and didn't realize that he died in December 19, 2009 at the age of 58. It was a Saturday. This year it will be a Thursday. He was survived by his father, who was his life long companion and care taker. http://en.wikipedia.org/wiki/Kim_Peek