I've got a few things that come to mind but I think it's this section of downhill chute. It's around 200 feet long, the top half is around a 55 degree angle and then it changes half way down to around 45 degrees. It's got an especially challenging approach at the top where I have to start at speed and then swing 90 degrees into the chute. It's got a rain rut right down the center that will grab the tire (front or back or both) and throw you off if you can't bust out. A few babyheads and roots but the real danger is a one foot high by one foot wide tree trunk right at the bottom, just off-center (by the time I get to the tree trunk I'm just hangin' on!). It's a definate do-or-die run; you either make it down upright or it would be a spectacular cartwheel.
My challenge to myself was to ride it (or at least try and ride it) before winter sets in. I've done it twice and I've seen a lot of people look at it and I've seen some tracks but I've never actually seen anyone else ride it, yet. It's a blast!