One of the most popular party activities in teacher Jennifer Wagner's Austin, Texas, fourth-grade classroom was a fast-paced book swap dreamed up by one of her room parents. Several weeks before their December holiday party, Jennifer's class parent sent home a note asking each child to bring in a wrapped book, new or gently used (she provided a few extras in case anyone forgot). At the event, the kids sat in a circle with their books while the room parent read a story. Whenever she uttered the word "the," the kids had to pass their book to the right; at the word "a," they passed to the left. Jennifer's students found the inevitable confusion uproariously funny. "The kids liked that they got to keep the book they were holding at the end of the story, but what they really loved was the crazy process," she says.