Don’t know what Rx or Ix are? Well don’t worry as there is (as usual) plenty of content to be had via blogs, videos, articles and more. This is a great video with Wes Dyer and Bart De Smet talking about Rx and here's one where Bart discusses Ix in detail.
Taking a step back, the team formed in the spring of 2006, creating composable asynchronous and event-based programs using observable sequences and using LINQ-style query operators has been one of the main focus areas of the team, resulting in Reactive Extensions (Rx).
Rx was first introduced to the public in April 2009 at the OSCON conference in Portland. Through rapid iteration, actively applying the “learn fast, fail fast” principle, the team released 8+ experimental releases before reaching its first major milestone; shipping the Reactive Extensions (Rx) as part of Windows Phone 7 (June 2010). Since then Rx has been the subject of many successful talks at venues like: MIX 2010, PDC 2010, MIX 2011 and TechEd 2011.
In June 2011, the official release for the .NET version targeting .NET Framework 3.5, .NET Framework 4.0, Silverlight 4 and Windows Phone 7 became available.