I get excited when I can compose asynchronous code without using thread or lock API's

A C++/CX Windows 8.1 sample app that demonstrates using the accelerometer.

Now see it transformed using Rx++


Create a ReactiveCommand and bind it to a Xaml button

Transform SaveAsync method to ReactiveSave

Introduction to Rx
Reactive Extensions Rx were born as a transformation of LINQ expressions which pull from a data source through a set of operators into an Rx expression where the data source pushes through a set of operators.

Personally, I recognized them as the generalization I wanted to make of a pattern I had popularized in a previous project. We called them Sender/Receiver, Rx calls them Observable/Observer

Observable and Observer
An Observable is a source of data. An Observer operates on data as the source provides it. An Observer connects to an Observable by Subscribing to it. Many Observers can connect to the same Observable. 

A Subject is both an Observable and an Observer and will pass the data sent to the Observable on to each of the Observers that are Subscribed to the Observable.

An Operator is a function that takes at least one Observable argument and returns a new Observable.

Web Resources
There is a lot of information about Rx. Most of the information is focused on the .Net version as that came first. More recently there have been other versions built.

A partial list of Rx implementations:
Aaron Lahmann, a friend (and one-time co-worker in the team where I was working on Sender/Receiver) wrote Rx++ and was talking to me about it at the time. I still did not know enough about it to jump on it at the time.

Eventually, I saw an article by Jafar Husain that linked to an RxJS tutorial that got me excited. I highly recommend taking the time to follow through the examples.