There is a typo on the main page http://standardmarkdown.com/, in the section “How can I help?”:

“Read the spec, run the test suite, and exercise our reference impementations.”

“impementations” → “implementations”

I couldn’t find a GitHub repository for the code of the website itself, or I would have made a pull request.

Edit: I see there is already a thread about this: http://talk.standardmarkdown.com/t/site-typo-s-one-to-start-...