 MonoDevelop
MonoDevelop is a popular, open source 
integrated development environment for the Linux platform, primarily targeted for the development of software that uses both the 
Mono and Microsoft 
.NET framework. MonoDevelop integrates features similar to that of 
Eclipse and Microsoft's 
Visual Studio such as 
Intellisense, 
source control integration, and an integrated GUI and Web designer. MonoDevelop integrates a 
GTK# GUI designer called 
Stetic.
[1] It currently has language support for 
C#, 
Java, 
Boo, 
Nemerle, 
Visual Basic.NET, 
CIL, and 
C++.