Say, you have a 2nd level domain name of your home town: my-town.us and you want to give away 3rd level domain names (like the-barber.my-town.us) automatically and for free to anyone requested (i.e. implement 3rd level domain hosting). How would you go about implementing it?
I thought about using wildcard DNS record *.my-town.us to point to a web app, which would make a redirect based on requested url. But that would not be any good, because redirect will, well, redirect instead of using the desired domain the-barber.my-town.us.