Clone a repo and checkout a specifc remote branch

Hi list, I've got a few questions from a friend that used git for the first time, I answered to all of them but the following.

Scenario: He knows the URl of a git repository which contains a few branches. He is interested only to a single specific branch. He expected to manage to clone the specific remote branch with a single command, instead he had to learn the following procedure:

$ git clone git://uri_of_the_repo localdir
$ cd localdir
$ git branch
* master
# OK, so now he cloned the whole repository and checked out the master branch
$ git checkout mybranch origin/coolbranch

Wouldn't be an improvement to let the user to specify which remote branch he want to be checked out after a clone? Something like: $ git clone git://uri_of_the_repo:coolbranch localdir to get a clone of the whole repository and to check out the origin/coolbranch remote branch?

I quickly discussed this scenario on the #git channel and a user
suggested to use the following procedure:
$ git init
$ git fetch git://uri_of_the_repo coolbranch
which was new to me, I tried it as follow:
$ git fetch git://git.kernel.org/pub/scm/git/git.git man
remote: Counting objects: 7319, done.←[K
remote: Compressing objects: 100% (1536/1536), done.←[K
remote: Total 7319 (delta 5640), reused 7290 (delta 5625)←[K
Receiving objects: 100% (7319/7319), 1.40 MiB | 110 KiB/s, done.
Resolving deltas: 100% (5640/5640), done.
From git://git.kernel.org/pub/scm/git/git
 * branch            man        -> FETCH_HEAD

but now I don't understand how to checkout the branch :-/

Ciao,