This is just some Linux stuff I've written or contributed to that you may find useful.
The C++ Video Capture library has a nice KDE video adjustment dialog, but it's still meant as a programmer's tool as evidenced by not having any downloadables except through CVS... KDbg is a very simple debugger which is it's main charm, I added the vector register support because I needed it for my raytracer. Mica is very useful if you need to show very large graphs, I was using it to represent the byzentine business logic involved in switching your phone carrier in the United States. The Java Joystick driver is just glue for using a joystick in Java, but it supports the same semantics whether you are using the Win32 joystick.dll or the Linux 2.4 input events, which is nice to have in a crossplatform library. I have my own version of this if you have problems with the sourceforge one.