Syntax highlighting hints
The syntax highlighting system on SO has some serious problems. It works okay for most C family languages (C, C++, C#, D, etc.), but it interacts horribly with others.
For example, OCaml and Lisp cause problems because of unmatched single quotes. It would be nice if users could create syntax highlighters for different languages and post them. If they were approved by enough users, they would become part part of the site and we could use them in posts.
The syntax might look like this:
Blah blah blah `inline code here`(language) blah blah blah. (language): block code here ... Blah blah blah.