If you are looking for radical, potentially disruptive ideas (rather than “this broke, any ideas how we can stop if happening again”) you can greatly increase your chances by taking the time and effort to disrupt the status-quo of how you run meetings and workshops. Changing the location, roles, participants (ideally involve an outsider as facilitator) and approach to the meeting can make a profound difference.
There’s tonnes of evidence that the environment can make a big impact on creativity so look for somewhere more inspiring and engaging free of distractions from business as usual (BaU). btw. booking a sterile boardroom at the local hotel for your idea workshop isn’t necessarily that much better than using the sterile boardroom at the office! Think more radically!
Science and technology museums often rent space. As might your local art of tech University. Your brain is affected by such triggering factors and will possibly change track in new surroundings. Even simpler, go outside! Many of my best (and potentially most courageous ideas) were born in the pub! Indeed some of the ideas that changed the course of science and modern society were born in coffee shops and bars (if you haven’t already seen it, this is a brilliant video about where good ideas come from, http://youtu.be/NugRZGDbPFU). Running an idea workshops in your local pub might seem a little strange (and possibly inhibit participation), but you might also consider