> Even "the current development/testing version: Python 3.2.2 rc 1
> (August 14, 2011)" isn't new enough here?
No.  (Where does the quote come from?)  The current development version is 3.3; its version number is currently 3.3.0a0, to mean it was not released yet.  3.2 is a stable release now; 3.2.2c1 is the candidate release of the next bugfix version of 3.2, which is one of the stable versions (with 2.7).

> So I'll have to find out how to install Python 3.3 in parallel to my 2.7.1
> Starting with "hg clone http://hg.python.org/cpython" now.
Yep, there’s no need to install.  Cloning http://hg.python.org/cpython#default will get you 3.3.  If you already have a clone for 3.2, you can also pull the default branch in your existing clone; feel free to ask for anything that’s not in the devguide or not clear.