Incredibly interesting app development platform that builds apps for all platforms (desktop & mobile, including linux, yay!) quickly with a single API. Open source, free, pay for premium support. Very, very interesting business.
Seems to be the best way to build cross platform mobile apps around. It's open source, free, and includes a cloud based build platform that will build an app for multiple mobile environments all "in the cloud". Easy.
Funky open source web app around task management that syncs and has a client across Mac, Win, iPhone, Android. Apparently no linux support. Built on top of Titanium from appcelerator.