Most drinking games have a lot of different rules and components—but not this one. There are no shots involved or "finish your drink when..." rules.
Drink when any of these situations or words come up.
Drink when the word "Portland" is seen.
Take a drink when you see the word "Portland". That means that the title sequence is a wild ride.
Warning: Whenever the scenes change, there's a "Portland" on the screen.
This is a really short list of rules, but it's a really effective game.
Trust.