The Concept2 Indoor Rower is ideal for challenges of all kinds. In last year's Games, a 1K row launched the hopper WOD. This year, Concept2 gave away an indoor rower to the top male and top female 1K row times. They've also invited all affiliates to participate in their Fall Rowing Challenge.
Greg Hammond from C2 sent over this link to a BBC Sports video. In it, Andy Hodge rows 100m in 15.5sec. If there's any distance that CrossFitters might take an elite rower, this is probably it. Anyone got sub 15sec?