Arcadia is a Light Integrated Development Environment (IDE) for Ruby language.
Editor: Arcadia is a Light Integrated Development Environment (IDE) for Ruby language written in Ruby using the classic Tcl/Tk GUI toolkit.
Some of Arcadia ruby ide project features are:

* Script editing, running and debugging support
* Source browsing, syntax highlighting, code completion
* Working on any platform where ruby and tcl-tk work.
* Extensible architecture. you can free download Arcadia 0.8.0 now.