bamboo-language - "Bamboo is intended to provide an implementation of Smalltalk and Strongtalk for both the iPhone and Mac OS X, leveraging Apple's Objective-C runtime, LLVM, and Clang.". There is not much content there yet, so it should rather be considered a statement of intent.
DeliciousSafari - sync Safari bookmarks with delicious. Alternative to bookmark sync via MobileMe? There are also iPhone apps for Delicious. And calendar, contacts, etc. can also be done as push sync via Google.
Enterprise scala actors: introducing the Akka framework - sounds a bit like OTP (the server platform for Erlang) for Scala. Could be very interesting, let's see.
Mozilla Labs Raindrop - reminds me somehow of Radio Userland (not just because of the desktop web server, but also because of the objective).
pier - anyone who wants to play around with Seaside and applications for it on the Mac, here is a project that has built a Mac application around a Squeak with Seaside and a CMS. It makes quite an interesting impression (and yes, today is once again dig-into-google-code-projects day ...)
Snow project - a GUI library for abcl (armed bear common lisp) based on Swing.
xmlisp - and yet another MCL descendant (or perhaps rather a CCL descendant). So a Common Lisp on Mac, this one with specific extensions for 2D and 3D graphics and game programming. Reminds a bit of Processing at first glance.