Ruby/Perl/PHP, 52
$b='$b=%c%s%c;printf$b,39,$b,39;';printf$b,39,$b,39;
Copied verbatim from Christopher Durr's Perl quine.
This is rules abuse. Ruby and Perl are definitely not the same language, nor is Perl a subset of Ruby (most of the linked Perl quines don't work in Ruby, for example). But Ruby was designed to be able to look a lot like Perl if you want it to, and this happens a lot when golfing.