Lustr is a Ruby DSL for GUI development. Write a Lustr GUI once, and you can:

- Run it with Ruby controllers on the desktop, using wxRuby, on all major operating systems, including Linux, OS X, and many versions of Windows
- Use the same Ruby controllers and run it in a JVM using JRuby and Swing
- Run a code generator to convert the UI to Flex/MXML or XUL, to tie into your ActionScript or Javascript controllers

More details on Lustr can be found at home page[http://www.codecorps.org/moinmoin/index.cgi/Lustr]
or on the RubyForge[http://rubyforge.org/projects/lustr] site.