dunan is a little program that shows animated Miku Miku Dance 3D models on the desktop. It also supports Miku Miku Dance motion files and has a built-in settings menu and mouse and keyboard control functions. It can optionally play MP3 or Ogg files. It uses real transparency, and can be used with any window manager. It has very few dependencies, and works fine with compiz.
sbs_proc (Side by Side Processor) is a simple command-line application that processes side by side stereo images (such as those produced by some mobile phones) and converts them into monoscopic versions which can be visualised on non-stereo systems. It works on .jps files and produces .jpg outputs. It can produce anaglyph (red/blue glasses required) or right or left images.
RoseThorn is a cross-platform library for 2D and 3D games running on GNU/Linux (and possibly other Unix-like OSes) and Windows. Features include: hardware accelerated 2D and 3D rendering; Ogg and WAV Sound support with OpenAL; Lua scripting; BMP, JPEG, and PNG image loading and saving (from screenshots); easily created and modified user interfaces with XML and CSS, combined with Lua event handling; separate 2D and 3D libraries; support for multiple fonts in both TTF and bitmap formats; support for OBJ, 3DS, MD5, and RTM model formats; skeletal animation (a work in progress); support for UDP and TCP networking; thread and mutex support; a Simple Shader API; 2D animated sprites; and some basic cryptography support. There is simple event management, with key/mouse bindings easily customized from the in-game console, config file, command line, or GUI.