Drink Every Time:

1. You see a can of Pepsi
2. Anyone yells "Hello!!!"
3. Anyone gets killed and/or infected
4. Anyone mentions "infection"
5. Anyone pukes blood
6. You see a flash/glimpse of someone running by
7. Anyone mentions "staying alive" or "survival"

Want to get wasted?

Anytime a Zombie goes "Graaaar!" (the zombie noise. You know the one.)