I\'m using emacs 24 on OS X and have the strange problem that I\'m unable to see any color codes. Emacs seems to just ignore them. My motivation is to see colored output from cm
So it turned out that the problem was caused by zenburn-theme 1.2. There was a bug there with the ansi-color-names-vector that's fixed in version 1.3 (released just now). If you're experiencing a similar problem make sure you upgrade your version of zenburn.