Gosui is a project mainly written in Ruby, it's free.
UI Library for Gosu
Gosui is a UI library for the Gosu Game Library (current version 0.0.4)
Currently Supports
Requirements
:: Next Milestone 0.1 :: I plan to have the following functionality for the 0.1 release. The status reflects the progress for the 0.1 release. If you see 'Done' it means that it has the functionality originally planned for the next milestone.