Chapel And Sherman.
A kid was seen riding backwards on his bicycle for the duration of an entire city block. He is seen in this image to the left, actually turning the corner and riding on the sidewalk, still in backwards mode.

Despite the fact that there was traffic, and he couldn't really see where he was going, the kid kept going down the street basically forever. There is still, to this time, no determination of the length or duration this individual is capable of riding backwards on a bicycle.

Click here for quicktime clip.