ChemDoodle is a fully functional chemical drawing application. In addition to being multi-platform, it natively reads and writes many common file formats, including ChemDraw's CDX and CDXML. It provides a number of widgets, a complete templating system, and access to public databases of common molecules.
Wally is a Qt4 wallpaper changer using multiple sources like files, folders, FTP remote folders, Flickr, Yahoo!, Panoramio, Ipernity, Photobucket, Buzznet, Picasa, Smugmug, Google, Vladstudio, and deviantART images. It is available in many languages. Supported Linux window managers are GNOME, GnomeShell, KDE3, KDE4, XFCE4, BlackBox, FluxBox, Window Maker, and FVWM (experimental).
CSpec is a behavior-driven development framework for C. It provides a spec framework for describing the behavior of the functions of your system. The syntax is inspired from RSpec to be as legible as possible. The source code is as portable and as light as possible to make it easy to run the library on embedded devices.
Virtual MIDI Piano Keyboard is a MIDI event generator and receiver. It doesn't produce any sound by itself, but can be used to drive a MIDI synthesizer (either hardware or software, internal or external). You can use the computer's keyboard or mouse to play MIDI notes. You can use the Virtual MIDI Piano Keyboard to display the played MIDI notes from another instrument or MIDI file player.