Vu is a user interface toolkit written in Ruby. Behind the scenes, it uses Cairo for rendering and a thin Gtk layer for managing windows (this can be replaced with win32/Carbon/XLib/SDL/...). Theming can be implemented very easily using built in Ruby features. Vu's goal is to create a (fairly) pure Ruby toolkit that works well on all platforms and is extensible to all GUI needs, providing an easy to understand and extend API and performance comparable to lower level toolkits. Eventually, it should expose a rich set of user interface components, inter-application and inter-toolkit drag and drop/copy and paste support, eye pleasing themes with support for accessibility features and translations, all from the comfort of Ruby.