dynamically generated /etc/motd using fortune, cowsay & lolcat,save it as /etc/update-motd.d/95-lolcat.Google `pam_motd` or `update-motd` for more details of dynamically generated message-of-the-day.

95-lolcat

#!/bin/bash
# see: http://blog.tomtung.com/2009/11/cowsay-fortune
#      http://www.commandlinefu.com/commands/view/3584/remove-color-codes-special-characters-with-sed
#      https://github.com/busyloop/lolcat
#      https://github.com/dorentus/mruby-lolcat-bin
#
#      requires `fortune`, `cowsay`,
#        and ruby gem `lolcat` or its mruby version equivalent

export LANG="en_US.UTF-8"
export PATH="/usr/games:/usr/local/bin:$PATH"

printf "\n"

msg=`fortune -a -s`

# Randomly pick a mode of the cow
modes=("" -b -d -g -p -s -t -w -y ); mode=${modes[$(($RANDOM % 9))]}

# cowsay or cowthink?
cowdos=(cowsay cowthink); cowdo=${cowdos[$(($RANDOM % 2))]}

# Radomly pick a cow picture file
speaker=`cowsay -l | sed '1d;s/ /\n/g'| sort -R | head -1`

# lolcat
cmd_lolcat="$(command -v lolcat_m)" || cmd_lolcat="$(command -v lolcat)"

# That's it ^^
echo "$msg" | $cowdo -n -f $speaker $mode | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" | $cmd_lolcat -f

printf "\n"

lolcat-banner.sh

#!/bin/bash
# see: http://blog.tomtung.com/2009/11/cowsay-fortune
#      http://www.commandlinefu.com/commands/view/3584/remove-color-codes-special-characters-with-sed
#      https://github.com/busyloop/lolcat
#      https://github.com/dorentus/mruby-lolcat-bin
#
#      requires `fortune`, `cowsay`,
#        and ruby gem `lolcat` or its mruby version equivalent
#

printf "\n"

cmd_sed="$(command -v gsed)" || cmd_sed=sed
cmd_lolcat="$(command -v lolcat_m)" || cmd_lolcat="$(command -v lolcat)"

fortune -a -s | $cmd_sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" | $cmd_lolcat -f

The script itself works for me, but lolcat does not want to work when I open an ssh connexion...
It simply stays blank.

Try this command
" sudo chmod a+x /etc/update.motd.d/* " (without double-quote)