I've been doing some research on Castle DynamicProxy for an upcoming screencast that I'm working on. So far, it's a pretty simple tool to use, and feels very familiar to other AOP tools that I've used. Here's a 101-level example:

And here's the output of that example:

Not particularly elegant, but by using an IoC container you can make it much cleaner and transparent (which will also be part of the screencast).