cowsay is a little utility that as you can guess draws a cow on the screen and can display text with it
< hello >
-------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
However there are lots of nice options
entering
cowsay -f tux hello
draws a pic of tux
< hello >
-------
\
\
.--.
|o_o |
|:_/ |
// \ \
(| | )
/'\_ _/`\
\___)=(___/
If you use the -l option you get a list of all the different ascii art files it can load in
Cow files in /usr/share/cowsay/cows:
apt beavis.zen bong bud-frogs bunny calvin cheese cock cower daemon default
dragon dragon-and-cow duck elephant elephant-in-snake eyes flaming-sheep
ghostbusters gnu head-in hellokitty kiss kitty koala kosh luke-koala
mech-and-cow meow milk moofasa moose mutilated pony pony-smaller ren sheep
skeleton snowman sodomized-sheep stegosaurus stimpy suse three-eyes turkey
turtle tux unipony unipony-smaller vader vader-koala www
so there are lots of options for characters.
You can also combine this with fortune which is another little program that comes up with random quotes from a large database of options
psutton@e-machines:~$ fortune | cowsay
______________________________________
/ Tell the truth or trump--but get the \
| trick. |
| |
| -- Mark Twain, "Pudd'nhead Wilson's |
\ Calendar" /
--------------------------------------
\ ^__^
\ (oo)\_______
(__)\ )\/\
||----w |
|| ||
If you put what you want at the end of .bashrc then when you start a console it will display the result and you can use it as a greeter for people logging in.
As always more info can be found in the man page
man cowsay