Raring Ringtail is the code name of next Ubuntu, Ubuntu 13.04 which will release it's first alpha in December 1 2012 . Final version will take some more days and expected to release in 26 April 2013. We don't have much information about Ubuntu 13.04 which kernal version and which Nautilus version only we have it's code name.
Ubuntu 12.10 release today itself . We already made reviews and videos but there will be some changes in Unity dash system . In Ubuntu 12.10 beta 2 they added Amazon affiliate and some tweak in Unity dash. Video and other lens improved a lot from beta 1.