Laughing is good for learning.
That's the theory of Doni Tamblyn and Sharyn Weiss, authors of The Big Book of Humorous Training Games (McGraw Hill, 2000).
Try the 10-minute “Brain Fry,” designed to warm up a group for brainstorming:
Create teams of four. Tell each team to pick the first “target person.” Then ask them to quickly choose who will go second, third, and fourth.
The first target person faces the rest of the team, lined up like a firing line.