According to http://rakudo.org/how-to-get-rakudo/ , Perl 6 is just a specification. What changes do you see in the specification between now and Christmas?
Note that the 'Synopsis' has been demoted to be closer to a set of design docs than a formal specification - it's more about the test suite these days (cf first two paragraphs of http://design.perl6.org/).
Jnthn made a list of things that are supposed to be fixed by Christmas [1] as well as a list of things that probably won't make it into the 6.0 release [2].