rj@raconteurlaptop:~$ ffmpeg -y -f x11grab -r 25 -s 1366x768 -i :2,0 -f alsa -i plughw:2,0 -acodec libmp3lame -ab 128k  -sameq ~/Desktop/nethack.avi
ffmpeg version 0.8.6-6:0.8.6-1ubuntu2, Copyright (c) 2000-2013 the Libav developers
  built on Mar 30 2013 22:23:21 with gcc 4.7.2
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[x11grab @ 0x9606a20] device: :2,0 -> display: :2,0 x: 0 y: 0 width: 1366 height: 768
[x11grab @ 0x9606a20] Could not open X display.
:2,0: Input/output error