Undeadly.org has a writeup on something I’ve needed but never done: accessing your console’s X desktop remotely, using x11vnc. There’s an earlier ‘Stupid SSH Trick’ for using ProxyCommand.
A running description of activity related to DragonFly BSD.
A related ‘stupid trick’ is to use a SixXS.net IPv6 tunnel to get a static address you can hang a DNS name on, for initiating a direct IPv4 tunnel to accomplish all of the above.
This is equivalent to using a dynamic DNS service, but handy when you own a domain with registrar-provided DNS but no machines to run your own DDNS service on — and are behind firewalls you don’t control, etc, etc.