My favorite author, Steven Brust, has written a Firefly fanfic novel that is free and online, and 160+ pages long. You can find it here. It's set between the series and the movie, apparently. Certainly something excellent to read while I'm waiting for the next Vlad book to hit in the summer... And, y'know, Brust writing fanfic? How delightfully weird. I am ecstatic and will be putting it on my laptop to read.