Read Amos 3:7.
Why is a prophet important?
Tell some facts about the current prophet.
Play a trivia game and see who knows the answers to the facts you told them.
Make a card (or a bunch) for the prophet.
Take a picture of everyone around the birthday cake. Sing "You've Had a Birthday" and eat birthday cake and ice cream.
Send the birthday cards and the picture of everyone to the prophet for his birthday.