In these days of high definition videos everywhere (even YouTube), only the truly geeky would decide to watch their movies in ASCII text in a terminal window. The surprising thing is that some videos are even fairly watchable.
To do that you just need to install mplayer and for that just write this command in terminal line:
$ sudo apt-get install mplayer
Then, to actually watch the movies from a terminal window, use the following syntax, replacing MovieName with the filename of your video.
$ mplayer -vo caca MovieName.avi