Terry Cavanagh initiated the most recent attempt after playing an RPG-maker chain game. This "chain" structure makes the organisation problem a lot simpler - there's no pre-planning and consensus required, everyone just looks at what's gone before and adds their own thing from there. Way easier to get off the ground. Terry decided on a schedule of 3 days per person, which turned out pretty well I think: it's long enough to do something that's not entirely trivial, but short enough that you can accurately plan for it - once you've spend a week on something then it could take months. And we ended up with strong themes coming through, colours and sounds and mechanics and ideas and words and images, just from doing things in order looking at what others had done, without having to agree on them in advance.
Terry will no doubt be typically humble and try not to take much credit, but he's responsible for prodding and poking and organising to make this happen, and actually making firm decisions for us when we'd all just keep coming up with more wild ideas. Thanks, Terry.