Maybe I am crazy, but I just love the adventure of exploring new places and going where most people don't.  Rock Creek doesn't look like a great play run, but the section I saw looked like continuous III with a couple of must-miss strainers.  Nothing too hard, and I'm not expecting great water quality, but for me it just seems like a cool thing to go experience, mostly because I never have.  I've actually never heard of ANYONE running it, and I've been asking about little-known runs in the area.  I was really surprised to find it listed on the AWA site as a run.  There's no description, which of course only raises the allure for me.  And the best part is it's hidden in plain site--right dead center in the middle of the city!