Yes is Funnier than No

So the first rule of Improvisational Theater, according to Brad Miller, a fellow Peace Corps volunteer and avid Improv fan, is that "yes" is funnier than "no".

As such, one of the most basic warming up excercises for improv is called Yes, Let's:

Pick a group activity, like throwing a party or organizing a picnic. One player starts, saying "Let's ..." filling in what she wants to do. Then she starts actually doing what she said she wanted to do. A second player jumps in, saying "Let's ..." do something else, to advance the group activity. Both players say "Yes, let's do that" and start doing whatever suggested. Third player jumps in, suggests what to do, and again all players loudly agree to do it, and actually do it. Continue till everyone has suggested something.

The point of the exercise is to get players to reflexively accept offers. The reason this is a good thing is that a no answer stops all possible further action in a scene, whereas a yes answer provides many opportunities for taking a scene in a bizarre and amusing direction.