Blossom 1.0.0-beta.1 (SproutCore 3 candidate)
gist.github.com
gist.github.com
Take the browser and cut the cruft of HTML and CSS: what you're left with is a cross-platform JavaScript runtime with high quality graphics, audio, and networking libraries with a built in database. There's no reason such an environment couldn't compete with "native" applications.
Once WebGL and the audio APIs are supported on mobile devices with two or more cores things are going to get very fun.
Is there anything in GPLv3 that would disallow a commercial website using the library?
(Blossom can also be used to generate native mobile apps, in which case you obviously need to buy a license for closed-source apps.)