A free IDE for C#, VB.NET, & Boo projects on Microsoft's .NET platform
SharpDevelop is the open-source IDE for the .NET platform. Write applications in languages including C#, VB.NET, F#, IronPython and IronRuby, as well as target rich and reach: Windows Forms or WPF, as well as ASP.NET MVC and WCF. It starts from USB drives, supports read-only projects, comes with integrated unit and performance testing tools, Git, NuGet and a lot more features that make you productive as a developer.
ASED is a Tcl/Tk Editor written in pure Tcl/Tk using the BWidget Toolkit. Features included: multifile editing, syntax-highlighting, command-expansion, undo/redo, autoindent, find/replace, file-browser, help-system
An open source IDE for AROS Research Operating System
SCUMM Developer is a project in which we will try and make an IDE which will run a set of tools to manipulate or create your own SCUMM Game. We plan on supporting all versions and possibly even GRIME.
Trac is an enhanced wiki and issue tracking system for software development projects. CruiseControl is a framework for a continuous build process This VMware Virtual Appliance integrates both software to make a complete SCM & Project Managenent Tool.