Kindergartners are big on the pinky swear. When J was in kindergarten I thought it was weird when he said to me one day, "I pinky swear mom!" (he wanted something, and took the solemn oath of pink swear that he would do something for me in return.)
Today, A came home from kindergarten pinky swearing to his brother that he'd play with him.
I love 5-year-olds.