Pong in the shortest code The challenge is simple. Give the shortest code possible to reproduce the classic 2-player game of pong http://en.wikipedia.org/wiki/Pong .  The level of graphics and functionality should be as close as possible to this javascript demonstration http://codeincomplete.com/posts/2011/5/14/javascript_pong/demo.html (but without the extra options you can click on on the left or the frame, fps etc. information in the bottom right).

As always the code must be written in a free language (in both senses) and should be runnable on linux. Any libraries used must also be free, easily available and not be written for the purposes of this competition (and also not already contain a working version of Pong!).
sed, 35

Raising the bar a bit with a postage-stamp sed meditation.

s/&gt; / &gt;/
s/ &lt;/&lt; /
s/0&lt;/0&gt;/
s/&gt;1/&lt;1/


The meditation is enjoyed on stdin/stdout on two computers, not necessarily connected by a network.  The meditation begins in the state

0         &lt;       1


with guru zero on the left and one on the right.  The angle bracket moves left and right, and if a guru maneuvers their number to contact the cursor as it comes to their side, their score is increased by one, and they become elated with joy.

The meditation is initiated by typing the above state into sed -f medi.sed, and the computer responds with the next state.  The dutiful guru types that state into the meditation, reading aloud the next key they will press, with both gurus pressing the holy key to enter the future at the same time.  The dutiful computer replies with the next state.  This, in turn, is read aloud while typed in unison as with the last.  Continue advancing into the future until infinite bliss is achieved.

Gurus desiring a challenge may play 'turbo' mode, wherein the gurus attempt to collaboratively predict the computer's next state, and typing it into the prompt instead of the current state.  Gurus will have the wisdom to verify agreement between their predictions before entering the future.