Fifechan is a lightweight cross platform GUI library written in C++ specifically designed for games. It has a small yet powerful built in set of extendable GUI Widgets allowing users to create virtually unlimited types of widgets. Fifechan supports rendering in SDL, OpenGL, or Allegro out of the box or it can be adapted to use any rendering engine the user requires. Events are pushed to Fifechan which allows users to use any input library they wish or they could use the built in input handling through either SDL input or Allegro input. The primary goal for Fifechan is to keep it extendable, lightweight and still be powerful enough to use in all types of games out of the box.
For more general information about fifechan and/or downloads related to fifechan please visit the fifechan homepage at http://fifengine.github.com/fifechan/.
If you want to get involved with fifechan development come check out the official IRC channel #fife on freenode. Drop us a line there and we can help you get started!