We have found that creative meetings are self-limiting. Once one person has an idea, everyone gathers around that idea and refines it, but they rarely come up with more ideas.
Creative meetings are also more difficult for introverts, and we have come up with a solution to that.
We now send out the meeting schedule two days in advance and ask everyone for input and ideas before the meeting starts. Extroverts can stop by and talk and introverts are encouraged to email.
Then we have thee meeting to discuss all the ideas everyone came up with. We get many more diverse and creative ideas this way.