Here's what I did:
# sudo cp /etc/apache2/mods-available/userdir* /etc/apache2/mods-enabled/That was easy! The userdir.conf was already set-up to disable this feature for user root and to serve files from /home/*/public_html so to test that it works I did:
# sudo /etc/init.d/apache2 restart
# mkdir ~/public_htmland then typed http://mysite.com/~jah/ into my web browser to check that the index file was served. yay!
# echo yay! > ~/public_html/index.html