GitHub README’s feature nice syntax highlighted code blocks with the triple tick notation.

``` css
body { font-family: sans-serif; }
```

But as this syntax is a part of GitHub Flavored Markdown and not the vanilla Markdown variety, TextMate does not recognize triple ticked code blocks, which can lead to ugly sections of the document. Take this example from desandro/textmate-bundle/README.mdown

I resolved this by modifying TextMate’s Markdown Language Grammer, adding in the triple tick pattern for raw_block.

raw_block = {
  patterns = (
    { begin = '(^|\G)([ ]{4}|\t)';
      name = 'markup.raw.block.markdown';
      while = '(^|\G)([ ]{4}|\t)';
    },
    { begin = '(^|\G)```';
      end = '(^|\G)```';
      name = 'markup.raw.block.markdown';
    },
  );
};

Bingo.