What counts as a wildly challenging idea in applied computer science? A new programming paradigm? I actually can't think of anything I would drop everything to pursue right now, and I suspect most people are the same way. I think it's naive to assume everyone would do something wonderful if only they were unfettered by corporate shackles. For most people writing a good ORM or programming language would be an achievement.
I could probably make a list of things, but they'd be specific to my particular needs. Generally, each week, I think of one or two services or products that I wish I had.
At this very moment, I wish I had a service that would crawl the web and extract recipes and save them in a standard format with standardized ingredients, units of measure, equipment, and procedures. But, that's just me.