I was just curious, here are my results....
DNF: Nope, almost once during a marathon though. I finished and ended up with a stress fracture.
DQ: Nope, pretty hard to get DQed as a distance runner, unless you are like Baala and knock dudes down.
DFL: Oh yeah, just once...but it was a two man race. I got second.
How 'bout you guys? Any good DNF/DQ/DFL stories?