I am playing the "X-Com - Enemy Within" drinking-game. This one is from my own design, the rules are as follows:

Take a sip of your beer beer everytime when:

-When you are called "commander".
-When a cutscene starts.
-When a soldier misses a shot
-When a soldier is flanked
-When a soldier is critically wounded.
-When a terror mission pops up.
-When you research a new technology.
-When a soldier levels up.
-When a soldier gains a medal
-When you shoot down a UFO

Take a shot or finish your beer when:

-When a soldier dies
-When a soldier is mind controlled
-When a soldier kills an alien (with full HP)with one shot.
-When a Rocket misses.
PS: I mess sometimes up, I know that lol.