Because is an excellent game to show the difference between horizontal narrative offers and vertical narrative offers. Vertical narrative offers advance the scene. Horizontal narrative offers take the scene sideways, often derailing a scene completely.
Players circle or pair up. First player makes a statement (e.g. “The dishwasher was broken.”) The second player then replys by starting with “Because…” inserts the first players’ statement… and then adds to the story with another offer (e.g. “Because the dishwasher was broken Janet was running out of dishes.”) The next player then repeats the last line, starting with “Because…” and adds another offer to the story. This continues until all of the story elements are covered.
To eliminate the problem of shelving caused by horizontal narrative offers.
Make sure your group uses all of the offers, not just the last offer made, as it will remind them of the focus.