The Bananas Game is a very simple, keep a straight face, type game (further instructions in the ppt). In many cases it would work without a ppt or anything materials at all. But my students were having a hard time coming up with questions. Every class I would hear, Your face, which is not a question and is not that funny. So now they can just read the ppt. If they laugh click laughing cat, if not then grumpy cat.
Play this now, at the beginning of the semester. Once the students get used to each other it will be harder to get the nervous laughter going.