For us we sit around a table, someone has a book and a pencil (and sure enough some pizza
) . We all share our ideas and we write them down. We toss around a object and you cant speak unless you have it, this way we keep the session orderly. We then go through the list for plausible ideas that could work then we think about those more and test them. The ideas that are not used are still in the book and might prove helpful in future games. And more ideas and problems useally pop-up
. More ideas useally come later, even untill the last build day!
hope this was helpful