Print your copies of the two PDFs below. The first one is the worksheet with the key, and the second contains the cards for the gallery walk.
Cut the "Break the Code" copies in half horizontally. Cut out the gallery walk codes as well as the message for the winner.
Fold up the message for the winner and insert it inside of a balloon. You can also add another prize such as candy or a small toy.
Blow up the balloon.
Draw a sheep on the balloon using sharpies.
Put tape on the gallery walk cards and hand them out to the kids. Let them post the cards up around the room. Then you can work together to find all 29 together. Let the kids break the code using the key in groups or individually. If you have clipboards, whiteboards, or hard cover books for them to write on I would highly recommend using those. Make sure you tell them not to blurt out the verse or cheat. The first person to break the code can pop the balloon and get the prize.