Ummm, well, LLVM and Bonjour come to mind, and then there's a little-known project known as WebKit for which Apple is the main sponsor :-). They also do tons o

Ummm, well, LLVM and Bonjour come to mind, and then there's a little-known project known as WebKit for which Apple is the main sponsor :-). They also do tons of smaller stuff - as a ruby programmer, I appreciate Apple's sponsorship of the RubyCocoa project, and the fact that they have hired Laurent (the main programmer for RubyCocoa) to develop the next-generation MacRuby implementation, which provides free bridging between ruby and Objective-C