One interesting new business is taking hold in Los Angeles, and I would imagine elsewhere: Food trucks. These are like the old-style catering trucks but they visit different neighborhoods with food you'd actually want to eat. They roam about and you can find out where they're going to be on their websites or via Twitter.
This page tracks a number of them, including Barbie's Q, which is the only one there I've tried so far. About once a week, they park themselves for a few hours in a business district not far from my abode and they sell pulled pork and brisket sandwiches, primarily to folks who work in that area. I got one of each about two weeks ago and thought they were quite deelish. There are a few others I've heard about that may get my business if they come 'round.
That page, by the way, links to similar pages that track food trucks in San Francisco, Portland and New York.