When coding in Lisp or Scheme, some Emacs users prefer to have the parenthesis/brackets dimmed. The reason for this is that it makes it easier to see the things that matter like variable names.
Download parenface.el and then paste in the following snippet and you’re good to go. Don’t forget to customize the paren-face colour by doing this: M-x customize-group faces
Here’s a before and after shot (I’m using snow3 as the paren-face colour, the default provided by parenface.el is DimGray):
I’m not sure how useful it is to hide the ‘var’ and ‘function’ keywords. The cool thing is that all you have to do is alter the regex to suit your preferences.
If you like these kinds of snippets, check out Emacs-SOS, a StackOverflow search for emacs.