osx2x is a small Mac OS X application that lets you control other machines running either an X11 server or a VNC server using your Mac's mouse and keyboard. So if you happen to have a mac and either an X Windows machine or a machine running VNC on your desk you only need to use a single keyboard and mouse! This may sound like a very esoteric thing to need, and you'd be right, but some people have just that need, and thus osx2x was born.
2.3.0 to 2.4.0: Universal Binary. Dropped support for Mac OS X 10.2.