“Open source anti-theft solution for Mac, PCs & Phones.” I use hiddenapp.com, but this looks good. Another option is http://www.orbicule.com/undercover/mac/.

A great selection of VST and AU audio effects plugins for free download.

"A Mac OS X Leopard developer tool for debugging HTTP services by graphically creating & inspecting complex HTTP messages."

On the characteristic lack of usability in open source projects, and why. "The distributed, collaborative nature of open source software works for developer-level software, but works against user-level software. Imagine a motion picture produced like a large open source project. Different scenes written and directed by different people, spread across the world. Editing decisions forged by group consensus on mailing lists. The result would be unfocused, incoherent, and unenjoyable."

Spaced repetition! "Designed to help you remember facts (such as words and phrases in a foreign language) as easily, quickly and efficiently as possible. To do this, it tracks how well you remember each fact, and uses that info to schedule review times.

"The MacPorts Project is an open-source community initiative to design an easy-to-use system for compiling, installing, and upgrading either command-line, X11 or Aqua based open-source software on the Mac OS X operating system."

"WebKit is an open source web browser engine. WebKit is also the name of the Mac OS X system framework version of the engine that's used by Safari, Dashboard, Mail, and many other OS X applications."