AddType text/html .rb to vhost.conf.master
I just discovered a blog suggesting to add the AddType declarations to the apache vhost rather than hacking the mime.types file of the system.
Seems very logical to me:
So instead of describing within the tutorials how to edit the mime.types, you should add this:
AddType text/html .rb (AddType text/html .rbx)
to the mod_ruby part of the vhost.conf.master