Short story: I wanted to distinguish my terminal windows between local sessions, ssh sessions and vagrant sessions.

SSH_THEME="SSH"
VAGRANT_THEME="Vagrant"

set_th () {
  osascript -e "tell app \"Terminal\" to set current settings of first window to settings set \"$1\""
}

set_id () {
  osascript -e "tell app \"Terminal\" to set current settings of first window to $1 $2 $3 $4" #$@ does not work!
}

get_id () {
  cur_id=$(osascript -e "tell app \"Terminal\" to get current settings of first window")
}

ssh(){
    #!/bin/sh	
	get_id
    set_th $SSH_THEME
    /usr/bin/ssh "$@"
	set_id $cur_id
}

vagrant(){
    #!/bin/sh
	if [ $1 = "ssh" ]; then
		get_id
	    set_th $VAGRANT_THEME
	    /opt/vagrant/bin/vagrant "$@"
		set_id $cur_id
	else
		/opt/vagrant/bin/vagrant "$@"
	fi
}

The code creates a temporary variable of the current theme before switching. So, when ending the session, the original theme changes back instead of a fixed one.
Putting the above code in your .bash_profile: gives the following nice behavior:

Color coding your sessions is a great way to visualize things and make sure you do not take any unwanted action by mistake 🙂

Of course, the code can be used to wrap any application. For instance, one could use it to make the interactive interpreter of Python/Sage or terminal sessions using torsocks appear in different colors or even fonts.