The Dynamic Language Runtime (more info here) is a great way to spice up those boring old CLR applications. Not only has the DLR helped bring the dynamic keyword to C# 4, but it helps Python and Ruby live on top of .NET.
Using the DLR and IronPython, it's relatively easy to craft a calculated column, giving you the power to execute IronPython expressions over your data objects. What's more, you can import Python modules such as math, datetime, etc.
You can download the source code for this example here. The exact same code can be used for both Silverlight and WPF. You can learn more about IronPython by clicking here.