Enabling SSH access through the firewall

This isn't going to make any sense to the vast majority of you, and the others will point and laugh at something that can be looked up elsewhere. But I've been carrying this little piece of paper around for almost a year now, so I figure it must be important enough to write down somewhere a little more permanent.

At home:

    ssh -R 9722:localhost:22 servername

On the server:

    ssh -p 9722 username@localhost