Brainstorming - warm up exercises

Thank you both for the comments, but I’m actually looking for some exercises to kick of the session. I’m talking about 5-10min stuff to get into the mood, open minds, and get comfortable with spitting out crazy wacky ideas. I think I actually want that exercise to be unrelated to the problems/product we will be discussing.

As I implied it’s for non-designers, a group of 5 people that have not worked together a lot, particularly not in this way. I’m certain most of them are quite skeptical, so I want it to be fun. Surely someone has to know what I’m talking about?