New screenwriting app for OS X by Stu Maschwitz. I like how Jonathan Poritsky briefly describes it:
Slugline allows you to write in Fountain while making your script look like a formatted screenplay. It’s like Final Draft without all the headaches. It’s magic. And since your documents are always in plain text, you can take them with you anywhere.
Fountain is, of course, the plain text syntax for writing screenplays inspired by John Gruber's Markdown. I don't write screenplays, but I'm aware of the alternatives that already exist on the market (namely, Final Draft). Slugline, from what I see, looks like a mix of FoldingText and traditional screenwriting software: it's got automatic formatting of plain text for screenplay documents, deep OS X integrations, and a rich preview that, however, is still based on a plain text file. I also like the Outline view, which more Mac text editors should support. Plus, even John August seems to like this app.