Install figlet:
<code>
sudo apt-get install figlet
</code>

Now just run figlet with an appended text string:

<code>
tdd@tdd-laptop:~$ figlet wiki.lnxgeek.org
          _ _    _   _                           _                     
__      _(_) | _(_) | |_ __ __  ____ _  ___  ___| | __  ___  _ __ __ _ 
\ \ /\ / / | |/ / | | | '_ \\ \/ / _` |/ _ \/ _ \ |/ / / _ \| '__/ _` |
 \ V  V /| |   <| |_| | | | |>  < (_| |  __/  __/   < | (_) | | | (_| |
  \_/\_/ |_|_|\_\_(_)_|_| |_/_/\_\__, |\___|\___|_|\_(_)___/|_|  \__, |
                                 |___/                           |___/ 
</code>

figlet has many options, checkout the man pages.