This YouTube video has somewhat consumed my morning. Sure, on the surface it's just a compilation of clips from 100 movies. But I'm taking it as a challenge, and you should too.
Here's what you do: Watch the two-minute clip. When it's done, write down every movie you remember seeing in the clip until you can't remember any more. Then watch the clip again, and when it's done, write down any more you had forgotten. You can't write while the clip is playing -- only from memory once it's done.
After four passes, I've still only gotten 75 of the movies included. It's maddening. You go mad, too!