Ideas for a 10 minute group activity based on problem solving?

For a university assessment (I study occupational therapy) I have been asked to lead a group activity (for only 3 others) based on exercising problem solving skills but I'm struggling to think of something that will only last ten minutes! Any ideas?|||Try giving one idea then the next person trys to improve on that idea can keep on passing it on untill no one can think of any improvments