Bringing the Party to an End
As the children's parents begin to arrive, tell the children approximately how many other children in the world have died due to disease, malnutrition, starvation, and violence just during the course of the birthday party. Tell the children that if they had spent just a few minutes helping some of those unfortunate children instead of wasting time at this party, they might have actually saved one or two of them from a horrible death.
Emphasize that the children were much too selfish to care about anyone but themselves, and that they can never be forgiven for wasting such precious moments at a silly birthday party. Because, after all, those moments are gone, and so are the children whose deaths they personally contributed to.
Good luck, and happy partying!