Game types!
There are several different ways of doing improv theater and they are sometimes referred to as games.
LETTERS
Two players get a starting topic, for example something you might complain about on an everyday basis.
Then they're going to write a letter of complaint, but they will be taking turns and only write one word at a time, like this:
Dear
Sir
or
Madam,
I
am
writing
a
letter.