ShiVa3D archives (.stk) by Vague Rant at 7:41 AM EDT on June 6, 2011
Just been looking into ShiVa3D, a crossplatform 3D engine for Win, Mac, Linux, iOS, Android, WebOS and Wii, which stores all its assets in proprietary STK files. From a bit of searching, it looks like no one's managed to extract them as yet, so if anyone's interested in taking a look at one, here's the (only) STK from Supersonic on iOS (though it's originally a WebOS title):