I have encountered many Oculus Rift demonstrations with a skybox that has been rendered incorrectly and makes you feel sick when looking around in the oculus. I decided to implement a skybox that looks correct in the rift - note in the source code that the perspective correction and eye offsets are applied on the matrix passed to the skybox shader too.
Requires Oculus Rift plugged in and installation of npvr plugin for Chrome - download the file and drag it on the 'Tools -> Extensions' page. If the demo cannot find your rift then it will just render a single camera on screen. Use the mouse to look around or rotate your head with the oculus.