.Net

.Net is a platform developed by Microsoft that is built on a common bytecode called the Common Language Runtime (CLR), which is similar to Java's JVM.

.Net Framework classes
The .Net platform is said to be "managed" due to the way it manages memory. As part of this managed environment, there are a large number of classes defined in the standard .Net libraries.

.Net Languages

 * C#
 * Managed_C_plus_plus|Managed C++
 * VB.Net
 * ASP.Net

OpenSource .Net implementations
There are a couple of OpenSource implementations of .Net available including Mono and DotGNU.