This exercise is helpful for relieving nerves and for when a group is feeling too much pressure to be immediately funny.
Everyone stood in one big circle.
Two by two people improvise a short scene with the person next to them that is as boring as possible. The teacher helps by saying “boring boring boring” before the scene starts. At the end of the scene (about 5 lines or so) everyone gives it a huge round of applause as if what just happened was the most funny entertaining thing ever.