Yes, an embedded - yet EXTENSIBLE - markdown parser is included in Pacem JS.
Feel free to play with it, below.
By the way: this whole site renders markdown text as
html markup.
The underlying base parser for the PacemMarkdownElement is provided as-a-service in the foundations package of Pacem JS (thus usable in WebWorkers).
The actual component itself exploits this extensibility including - so far - a couple of custom Rules that allow to embed YouTube videos and Twitter status.
The process is quite simple: you define both the rules (either inline, block or code) and the output rendering mode.