The Irrlicht Engine is an open source high performance realtime 3D engine written and usable in C++. It is completely cross-platform, using D3D, OpenGL and its own software renderers.
CoolReader is fast and small cross-platform XML/CSS based eBook reader for desktops and handheld devices. Supported formats: FB2, TXT, RTF, DOC, TCR, HTML, EPUB, CHM, PDB, MOBI. Platforms: Win32, Linux, Android. Ported on some eInk based devices.
This program views calibrated bitmap maps (moving maps) on PocketPC/WinCE platform. Additionaly it supports using GPS device to retrieve user position and show it (with other marks) in map - making it very handy for geocaching.
PocketFrog is *THE* game library to rapidly write blazing fast games on the Pocket PC platform. It is implemented in C++ with an object oriented design. If your application needs to harness the raw power of your Pocket PC graphics, PocketFrog is for you.