To start our seminars on disruptive innovations, we use the example of Google Docs vs. Microsoft Office. We provide participants with some background info on Google Docs and then put them into the role of Steve Ballmer. How should he react to the threat (or is it really a threat?) of Google Docs? We have this discussion even before we get into the theory of disruptive innovation. Typically, the participants raise many relevant points (e.g. resource dependence, fear of cannibalization, etc.) already at that point. Here you can find the slides to kick off this exercise. There is also a video on Slate that helps to give a little background information on Power Point and Google Docs.