This went really smooth. For the record:

$ sudo apt-get build-dep git-core git-doc
$ wget http://kernel.org/pub/software/scm/git/git-1.6.3.2.tar.bz2
$ tar -xvjf git-1.6.3.2.tar.bz2
$ cd git-1.6.3.2/
$ make prefix=/usr/local all doc
$ sudo make prefix=/usr/local install install-doc
$ which git
/usr/local/bin/git
$ git --version
git version 1.6.3.2