Washboarding

In case you were wondering what I was whingeing about, this is a not-very-good photograph of what a washboarded road looks like.

This is not a particularly extreme example, but you get the picture: the track surface "folds" into a series of waves which make for very uncomfortable riding (if you have a nice hard racing saddle and no suspension) or a fun, roller-coaster ride (if you have a moon buggy).