This is a fairly random splattering of notes mostly for my own future reference.
Simple single-site hosting works fine with just an IP address, but I wanted (name-based) multiple-site virtual hosting. I modifed /etc/hosts to provide temporary local faux domain name resolution. This just allows me to play around with various domain names before registering them or setting up DNS.
Now for the actual virtual hosting. Virtual hosts are added by creating files in /etc/apache2/sites-available and then invoking a2ensite from the terminal. This and pretty much everything I need to do with the server is explained in the Ubuntu Server Documentation (and the TracOnUbuntu page).