Let every participant draw a card from the deck. Ask them to think of an attribute they have in common with the card in question. Let everyone introduce themselves with what they have in common with the card and ask them for an example. This exercise helps making unusual associations that warm up the brain for the brainstorm. Bonus: it will give you some surprising insights into other participants that you don’t get when just asking for their name and occupation.
Harry draws a card of ‘Nelson Mandela’. He introduces himself: Hello, my name is Harry and I am a student at Hogwarts. Just like Mandela I want to do the right thing and make the world a better place. That’s the reason I saved everyone in this school multiple times.