Powers of Ten is a cool 9 minute documentary made in 1977 that tries to put into persepective the size of our universe. I first saw it in Astronomy class in 1998. At the end, when they show the carbon nucleus in the man's hand, I pointed my laser pointer right in the center of the screen as a glowing red dot. The class, mostly sleeping, must not have noticed - but I heard my professor laugh out loud. That laser pointer provided me with endless hours of enjoyment in college, including but not limited to entertaining the class by pointing it on a professor's arse as he is writing on the chalk board.
Click here to watch the movie on Google Video.