Ever heard people complaining that when it comes to starting a business, there are no good ideas left? At best, that's an excuse. There are plenty of entrepreneurs who prove nearly every day that almost every existing industry has gaps that need to be filled. It just takes a savvy entrepreneur and a great idea to do it right.

Take your standard movie trailer. You go to the movies on a Friday, sit down and wait for the new Will Farrell film to start, and there is your usual barrage of coming attractions. In about half of them, you probably hear familiar songs like the Stones' 19th Nervous Breakdown or American Hi-Fi's The Art of Losing. The other half of the time, a song's so unfamiliar it may as well Norwegian folk music. That Norwegian folk music, though, is where the money's at. Recognizing that it costs studios time, effort, and sometimes a ton of money to secure the rights to mainstream songs, a handful of start-ups started producing music just for the trailers. And while you were bemoaning a lack of fresh ideas out there, companies like Immediate Music and X-Ray Dog quietly started making trailer music into an industry in itself. Every year they produce sample albums with more than 40 tracks of music clips that can be used in a wide variety of movie advertisements (and television for that matter) for a better price than the studio would've gotten for that Christina Aguilera song.

Remember: Just because you think there are no more good ideas, doesn't mean that it's true. Just check out X-Ray Dog's trailer reel: