Fun Fact: May 13th is National Frog Jumping Day in the United States, inspired by Mark Twain's short story "The Celebrated Jumping Frog of Calaveras County." This day is marked by frog jumping contests and celebrations.by johnataylor on TwosFun Fact: May 13th is National Frog Jumping Day in the United States, inspired by Mark Twain's short story "The Celebrated Jumping Frog of Calaveras County." This day is marked by frog jumping contests and celebrations.