U Dum is a game where
you, the player, tries to get the attention of another player in a variety of ways. After gaining their
attention, you immediately
shout "U Dum!" However, the defending player may preemptively shout "U Dum" after you have
attention, nullifying your initial attempt.
Todd: "Hey Blair, I learned something
you this weekend."
Blair: "Really? What's that?"
Todd: "I learned that U Dum!"