Want a quick and beautiful Markdown cheat sheet. Own Marked.app?
Visit the Byword markdown guide and download the source markdown file.2 If you prefer, you can download Fletcher Penny's MultiMarkdown documentation and use it instead or in addition to the Byword documentation.
Setup this AppleScript and trigger it with some kind of launcher (LaunchBar, Alfred, Keyboard Maestro, whatever floats your boat).
tell application "Marked" activate open "/Volumes/Macintosh HD 2/Dropbox/Notes/Byword Markdown Cheat Sheet.txt" end tell
That's it. You now have a system wide cheat sheet for MultiMarkdown that looks gorgeous. I keep mine in NVAlt so I have it no matter where I'm working.
I've also created a custom cheat sheet with just the features I tend to forget, like bibliographies, definition lists and table formatting. To display the actual MultiMarkdown so it does not render, simply surround the text with the "pre" tags or indent to make a block quote.
I don't need it often but how many people remember how to insert image links with dimension tags?1