http://sublimetext.userecho.com/s/attachments/201306/i_105.png
Scope coloring was first suggested by Douglas Crockford. So far the only plugin for Sublime Text 2 (that I know of) that implements scope coloring has been made solely for JavaScript at https://github.com/mazurov/sublime-levels.
It would be great if this feature could be implemented for all languages, especially Clojure and Scheme (for me).
Difference between scope coloring and syntax highlighting:
http://daniellmb.github.io/JavaScript-Scope-Context-Coloring/example/scope-coloring.html#fullmonad