Nevada
Reno, Nevada has a pretty weird policy about sitting along sidewalks. The city has declared sitting or laying down on a sidewalk unlawful. They say that it interferes with the primary purpose of the sidewalk and threatens public safety.
New Hampshire
In 1973, the state of New Hampshire declared it unlawful to pick up seaweed off of a beach. You're not allowed to disturb to remove the seaweed from the coast. Apparently, this is rooted in the idea that seaweed could be used as fertilizer and was a hot commodity.