AsyncIO is the new hot topic for Python 3.4 which was just recently released. In my opinion, AsyncIO is a big game changer for Python. Where it makes sense, many libraries are sure to port some or all of their code to take advantage of it. I'm going to show you my version of a client and server I wrote after digesting section 18.5 of the Python documentation and looking at a few examples on the web.
You will need Python 3.4 to run the sample files, or install asyncio (pip install asyncio) for Python 3.3. There is a backport of asyncio for 2.6+ but I didn't test my code on there.
Clone from git or save the files below
$ git clone https://gist.github.com/9627160.git
Open a Terminal (or command prompt) window.
$ python server.py
Open another Terminal (or command prompt) window and run.