We've updated last years technology preview to make it more tightly integrated with Revit 2011 and also to take advantage of some great new capabilities. For example, the new Analysis Visualization Framework API is shown off for the first time.
The Solar Radiation Technology Preview for Revit 2011 allows you to understand and quantify solar radiation on various surfaces of your building information model.
I installed it yesterday and started playing around with it. It is great to be able to see the results right within your 3D view. Check it out.