I found this post on the blackpig site quite interesting:
"Edward De Bono is often regarded as the father of lateral thinking in creative circles and has numerous tips and techniques which can easily be incorporated into any marketing planning session to produce some truly innovative results. One of the simplest is the PMI (Plus, Minus & Interesting).
With the PMI you don’t just produce a list of pro’s and con’s of an idea you also list interesting results too, for example if a business was to start giving bonus’ for staff who went a year without taking a sick day some of the ‘pro’s’ might be: motivating staff to work harder and bonuses would cover lost sick time pay. ‘Con’s’: might be that staff who are genuinely too ill to come to work become disgruntled. And the ‘interesting’: because staff force themselves to work whilst ill could it result in more sickness around the company?
Another relatively easy technique to encourage creative thinking and innovation is backwards brainstorming; in this you produce a list of points which would have the opposite effect of what you want, for example a business producing a new website may have points including being viewable in only one specific browser, not updating the content, having large images and making it difficult to navigate. From this list you then turn each point around to create a list of solutions."