2001: A Space Odyssey Explained
Pardon my ignorance, but the ending of 2001: A Space Odyssey always escaped reason for me. Now, it seems, someone has taken the time interpret the damned thing. Not to mention the fact that it's a nice piece of Flash work.
Warning: Give yourself a good 15-20 minutes if you intend to watch the whole thing. You can skip around if you want.