Other than showing off a cool trick, I can't think of a legitimate reason to do this. But for those interested, you'll need mplayer installed to play a video in ASCII text mode. If you don't already have it installed, run the following command to install it:

Ubuntu: sudo apt-get install mplayer

openSUSE (If you haven't added the packman repositories, you'll have to do that first here):

sudo zypper install mplayer

If you are looking for a video to test this out on, check out the trailer for Big Buck Bunny. You can download it by running the following command:

wget http://mirror.cessen.com/blender.org/peach/trailer/trailer_400p.ogg

To play the video in ASCII Text mode, run the following command:

mplayer -vo caca trailer_400p.ogg