Halfway into their famous 1964 road trip from La Honda, California, to New York City, Ken Kesey’s Merry Pranksters pulled up to a beach on Lake Pontchartrain and dropped acid. For the intrepid travelers, worn out by the July heat after days on the road in their exuberantly decorated Universal Harvester school bus, which wasn’t air-conditioned, the tepid Louisiana lake water was a welcome relief