I have a lump of code I've been given to edit. Due to the interesting way it's been created it has to live at the root of my domain... ie localhost/.
However, I want to be able to use localhost/oldapp to get at sites I had previously been working on.
# default for any not matched elsewhere - this goes to root of newapp on disk
<VirtualHost *:80>
ServerName localhost
DocumentRoot /var/www/html/newapp
</VirtualHost>
# now try to pick out specific URLs
<VirtualHost *:80/anothersite>
DocumentRoot /var/www/html/anothersite
ServerName localhost
</VirtualHost>
It's been a good 10 years 6 or 7 years since I've done this stuff and it seems I've forgotten how it should be done!

Use it or lose it I guess!