One of my favorite ways of working simultaneously is simultaneous brainstorming. In simultaneous brainstorming, someone asks the group to come up with ideas relating to a topic, just like normal brainstorming. When somebody thinks of an idea, they say it out loud, write it on an index card, and put it where everyone can see. (One idea per card, for ease of sorting later.) Saying it out loud inspires other people to have new ideas, and writing the idea down yourself prevents the group from bottlenecking behind a note-taker.
