Recently, Wolfram SystemModeler has been announced. The best I can do: let Stephen Wolfram speak - announcement at Wolfram Blog.
To us working with Mathematica and partnering with Wolfram for 22 years now, it is a big step further enabling us to building industry scale solutions for special sectors in process, manufacturing and other industries and helping industries to establish Mathematica as strategic product supporting their technical and scientific computing work-flows.
What we find so exciting about SystemModeler: it is a very general platform and it has the 2 layers we find so innovative (extending the Open Source Modelica language dramatically).
An engine that calculates results from computable representations of built-in symbolic-numeric methods - all programmatically manipulated from a symbolic system description. A stable and flexible underlying for, say, visual system component configuration and modeling, event handling, analysis and simulation.
A domain specific language with visual programming capabilities that's operational semantics is an industry-proof wide-purpose engine.