From DrinkiWiki

Drink once whenever

  • Jack kills somebody.
  • Somebody summarizes what's been going on in the past couple hours.
  • Something bad happens to Kim.
  • There's a split screen.
  • Palmer has a speech about how he won't trash his morals, you know, the usual bullshit.
  • Jack defies orders.
  • A CTU employee looks at another CTU employee suspiciously.
  • Somebody mentions the amount of time it will take for something to be accomplished (i.e., "The Delta squad won't be there for another twenty minutes").
  • Jack says "Damn" or "damn it"

Drink twice whenever

  • A CTU employee other than Jack kills somebody.
  • Some annoying authority figure shows up (Chappelle, Alberta Green, etc.).
  • There is an obvious lapse in continuity (i.e., Kim says that Gael is a mole and in the next scene we see him on the run).
  • Somebody mentions Terri (Season One doesn't count).
  • Somebody is revealed to be a mole/traitor, or an important object turns out to be a decoy/red herring.
  • Somebody other than Jack defies orders.
  • A main character dies.

Drink three times whenever

  • A supporting character from a previous season shows up (Nina, Mandy, Sherry, Kate, etc.)
  • CTU goes into lockdown.

Finish the drink whenever

  • The main villain changes (example - Gaines to Drazen).
  • The final minute does not include a surprise/cliffhanger.