I bought two big bottles of Diet Coke and one package of Mentos. I taped them together and added the directions, which included one of the videos from You Tube on exploding the bottles. I recycled the bow off of our homemade wreath so it would be "wrapped". The young man was very excited -- his eyes got huge and really lit up when he saw the gift. As Tim was getting out of the car, holding the bottles, other party goers gathered around with excitement. They even set them off at the party. The birthday teen said he'd always wanted to do that explosive experiment but hadn't gotten to. The total cost of this was $5, and it was a big hit!!