It exists and it is called PerlMonks, although instead of a certificate the site issues 'XP points' (they are a sort of game really, but don't tell anyone you are trying to impress) and 'node rep'.

Maybe we don't push the Tutorials section here enough, but there is a lot of good material there for newbies and not so newbies too. And in addition to tutorial material we have a huge number of online tutors just waiting for your questions (we call them 'monks' for some reason).

Talk a walk through the halls of the monastery and you'll find all sorts of interesting rooms, some of them better hidden than others.