Reverse SSH Tunnels - SSHing to a computer behind a closed network / firewall

For my of my recent project I need to work with servers behind networks and firewalls, where I can't SSH into simply.

In case you have similar situation, or you're just trying to SSH to your office computer, I hope this post will be helpful to you:
http://udiudi.com/2013/04/01/howto-reverse-ssh-tunnel/