This Is My Life

Parent 1: Knock Knock
Parent 2: Who's there?
Parent 1: Interrupting Child
Parent 2: Interrupting Ch--
Child: Mama!

(Seriously, though, Rosie has discovered Knock Knock jokes, as well as jokes in the form of "What did one ____ say to the other ____?" -- If you have any you suggest we teach her, please add them in the comments.)