Flu Outbreak Game
Pass out one playing card to 16 participants and keep an identical set of cards for yourself (ex., ace, 2, 3, 4 of spades, hearts diamonds and clubs).
Select a card at random (cut your deck), call on the participant who has the same card, and have him/her stand and remain standing until the end of the game. Explain that he/she has the flu and is going to spread it to two others.
Randomly select (shuffle the deck and cut it) 2 cards, have the participant with those cards stand, and explain they have caught the flu from the first participant and each will spread it to 2 others. Repeat this process until the card you select is for a standing participant. Explain that you cannot get the flu twice in the same flu season and once you have recovered cannot spread it to others. Select no cards for these standing participants. Eventually, you will select only cards for standing participants, and the outbreak will be over. There should be a few participants still seated, i.e. uninfected. Not everyone gets infected in an outbreak.
Repeat this process, but announce that everyone with a spade or diamond got vaccinated for flu so they can neither get nor give flu. They should remain seated when you randomly select their card. Half the time the first participant selected will be “immune” (have a spade or diamond) and there will be no outbreak. When the first participant has a heart or club the outbreak will end more quickly and “infect” fewer than half the participants.