Alec Bryte's Website Tales of an adventurous architect...

Channel9 has an excellent video on using Reactive Extensions and Observable/Observer patterns when designing asynchronous code. Think of all the code you had to write to throttle UI updades in a WPF grid or make continuous calls to web service when user types into an auto-complete textbox.

All of those scenarios are now easily achieved with Reactive Extensions.

http://channel9.msdn.com/Blogs/codefest/DC2010T0100-Keynote-Rx-curing-your-asynchronous-programming-blues