Reactive Extensions (Rx) was added to Codeplex.com:
The project is actively developed by the Microsoft Open Technologies, inc., in collaboration with a community of open source developers.
The Reactive Extensions (Rx) is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators. Using Rx, developersrepresent asynchronous data streams with Observables , query asynchronous data streams usingLINQ operators, and parameterize the concurrency in the asynchronous data streams usingSchedulers. Simply put, Rx = Observables + LINQ + Schedulers.
Find out more on: https://rx.codeplex.com/