In all the books I've read on reflection they often say that there aren't many cases where you want to generate IL on the fly, but they don't give any examples of where it does make sense.

After seeing Reflection.Emit as a job requirement for a gaming company I was curious where else it's being used.

I'm now wondering if there are any situations you've seen in the real world were it was the best solution to the problem. Perhaps it is used as an implementation to a design pattern?

Note I imagine PostSharp / AOP uses it.