I appreciate comments to the effect that we should look at markets we understand and problems we have solved. This is good advice and it's something we have don

I appreciate comments to the effect that we should look at markets we understand and problems we have solved. This is good advice and it's something we have done. We have a good list of ideas from that process. My intent behind this question to HN though, was to get people to talk about things THEY would do. In other words, fish for stuff we haven't thought of. I want to plumb the "unknown unknowns" a bit!