Sergey Dmitriev is one of the leaders of JetBrains, the people who gave us such wonderful tools as IntelliJ Idea and ReSharper. He's recently published an article on some exploratory development he's done called the Meta Programming System. He sees this system as an example of a broader movement which he calls Language Oriented Programming.
My colleague Matt Foemmel and I spent some time with him last week and were very impressed with what we saw. I'm very interested in this growing movement, one that looks to build software through closely integrated sets of DomainSpecificLanguages. There's other interesting players in this space - most notably Intentional Programming and Microsoft's Whitehorse work. It's an area to keep your eye on over the next few years.