Pennsylvania
Oddly enough, it's technically unlawful for a psychic to receive monetary compensation for a reading. This includes fortune telling, tarot card reading, and palm reading! Since all of these things are pretty popular, this "law" probably doesn't matter too much.
Rhode Island
In Rhode Island, it's illegal to race a horse on a highway. A public road is one thing, but a highway is totally off-limits! That includes racing or even testing the speed of the horse. Failure to comply could result in a $20 fine or 10-day imprisonment.