Back in the fall of 2008, when he was a DePaul University student, Scott Bolohan
decided to ride the 'L' for 24 hours. That's 24 straight hours. Now, I like my public transit, but that's kind of ridiculous. Though he did get a pretty interesting story out of it.
And speaking of Chicago's elevated train system, have you ever wondered what you have to do to be able to film on the 'L'? This pdf handout
explains it all.