An Exercise, similar to Three Line Scene. There is no Ask For.
2 players.
Player 1 says something that establishes a relationship with the other player. For example, "Hi, grandma."
Player 2 says something that establishes a location, while yes-anding the previous line. For example, "I'm so glad you could come to my knitting museum."
Player 1 says something that establishes an activity that yes-ands the relationship and location. For example, "Ok, grandma, we've got to take all this yarn out to the dumpster before the fire inspector arrives."
Getting an activity started, involving definite characters in a definite location, enables you to play nearly any scene-oriented improv game. Once the activity is going, it can develop, get disrupted, lead somewhere else. A plot can emerge. In three lines, you've created a solid, fertile foundation for an interesting scene.
To get the most out of this exercise, make your yes-anding as concrete as possible, and listen and watch your scene partner as closely as possible.
See also: Three Line Scene for a slightly harder, more performance-related version.