Again, I cannot help but follow up on Zack's post on How to Come Up With Ideas. In the modern days of hypercompetition, where today's state-of-the-art solution quickly become yesterdays news, you have to set an environment where you continuously come up with new ideas and new solutions. Creating such an environment is not an easy task, since people are... well, people.
With this in mind, I find especially Zack's first five points critical, but I would like to add two more items that I personally feel are missing.
Set an example
When working as a doctoral student it was mandatory for all researchers to attend research seminars given by visiting fellows. The department's head professor always attended these seminars, and it was always the case that the most "stupid" and obvious questions was asked by the head professor. On the surface, the questions looked stupid, but actually they were very much to-the-point.
This, of course, made all us doctoral students start asking "stupid" questions. Many of the questions asked were indeed stupid, but that didn't stop us since nobody frowned or criticized us. Over time, the questions grew more and more precise and the students started finding many gems of insight into the subjects that were presented.
As time passed, I started realizing that the asking of questions where deliberately to create inquisitive and questioning researchers out of students that were used to learn just enough to pass the exam. By setting an example, he created an atmosphere were questions were asked, and where it was expected that some of the questions were stupid, some where silly, but that was nevertheless what you have to do as a researcher: constantly ask questions.
People's minds work best when relaxed and when not forced to produce ideas. Adopting the view of treating it as an experiment and taking the occational break are good ways to ensure that people are relaxed and not trying to force ideas to come (which never works, at least, it has never worked for me). In general, if you enjoy the session, you will also be more relaxed and more ideas will appear. Some ways to make the occation enjoyable and more relaxed is: provide food (for some reason, many insight come to me when I am going to fetch an extra sandwich, or pouring a coffee), make sure you have plenty of time ("Hey guys! We need 10 new fresh ideas before lunch!" is a sure killer), and don't keep a strict schedule (It depends on the people involved, but maybe you could bring the lunch to the room instead of going out?)