SSH across a Layer 7 Filter

Every once in a while, I find myself in a situation behind some sort of device that filters a lot of traffic.  Most often, it's on my laptop at some facility (e.g., coffee shop) that only allows HTTP/HTTPS out.  For a while, I just listened for SSH traffic on port 443 (HTTPS) to connect through port-based firewalls.

 http://systemoverlord.com/2011/02/18/ssh-across-a-layer-7-filter/