A timeless holiday favorite for kids who love Elmo, Cookie Monster, Oscar the Grouch, and more Find out how Santa first came to Sesame Street and why we leave cookies for St. Nick on Christmas Eve. It's the night before Christmas-time to put out some cookies for Santa But how did this tradition start? Elmo's dad spins him a bedtime story about his great-great-grandmoster, back when Sesame Street was a very different place...