My friend Josh Newman is shifting his film production company to be a venture capital firm that will focus on growth opportunities in unsexy industries:
I think he's right about the gap in attention and money to that quadrant.
There are many opportunities in stodgy industries that go unexploited because it's not mobile / real time / social / insert-buzzword-of-the-day-here. I always enjoy Marty Nemko's blog, and he often champions unsexy business ideas. In his entrepreneurial ideas tag, you can read about his business ideas for organic perfume, food carts, velcro shirts, and more. His entrepreneurship tag has even more.
One more random thought on generating business ideas: look at segments where most of the businesses feel scammy — and then do the exact same business but in a buttoned-up way. Google "mystery shopping" to see what I mean by "feels scammy." Anytime dozens of weird AdWords pop up, you know there's real money being made, but often by scammy entrepreneurs.
Alex Mann awhile back had good tips for how to get into the entrepreneurial swing of things even if you're in college.