Google's Summer of Code is a really cool, really massive project focused on open source that first started back in 2005. It functions on a pretty simple concept: the company gives out grants to student developers (this summer they brought on 900 from a list of 6,200 applicants) to work on open source projects for the summer, and we all subsequently benefit in one way or another. Take a gander through the long list of projects on the menu for this summer, and click on any to see what the goals are.
Whether or not these goals are met by the end of the summer is another thing entirely, but there are some great projects and features on the list for such apps as Adium, Camino, Thunderbird, Inkscape and much more. Adium, for example, might gain features like basic voice chat, AppleScript and Bonjour support, while a juicy feature on Camino's todo list is Tabsposé, bringing the window management wonders of Exposé (much like the WebKit-based Shiira features) to the more Mac-like alternative to Firefox. In fact, one of the developers involved with working Tabsposé for Camino is blogging the effort, with a few posts already online covering developer-oriented topics like getting caught up with minor details and coding resources, but also including teaser mockups of what Tabsposé might eventually look like.
Long story short: Google's third round of Summer of Code looks like it will again do some great things for Mac OS X software and open source on a broader scale. Heck, those open source developers are even getting paid, which must be a nice change of pace for some of them. We'll keep an eye on what new features arise from this Google-funded coding powwow at the end of the summer.