Yes, and...

I learned this rule of improvisation at Kani Club, and have found it very useful in my teaching. (A statement of the rule and nine others is here: http://improvencyclopedia.org/references//David_Alger%60s_First_10_Rules...)

It is most useful for any activity in which you will ask people to create a story or some other content together.

It can be added to the Broken Squares activity -- in which "Yes, and..." is a great tool for solving the collective puzzle.