Metadown
Nice gem from Steve Klabnik that extracts metadata from and parses Markdown files. Embedding post metadata in YAML format at the top of the file is a common approach employed by several static site generators such as Jekyll, Octopress, and nanoc as well as NestaCMS, the CMS that powers this site. Nesta's metadata isn't pure YAML and at times I wish it were.
Wynn Netherland is a full stack web creative who lives in Texas. When he isn't trying to change the world at Pure Charity, he geeks out on The Changelog, writes about Sass, and occasionally speaks at conferences and meetups.