If you buy your Serenity CE DVD at Best Buy, you'll get a comic! At least for a while, I don't know how many they're releasing. It's a small, DVD-sized reprint of the first issue of "Those Left Behind," the 3-issue Serenity mini-series from Dark Horse, with a cover by Sean Phillips (from what I understand it's the original cover for the first comic, which was replaced when they got the idea to do the cast covers; it was later used on the back cover of the trade paperback).
Inside you get the complete first issue, with promos for more Serenity items from Dark Horse and for Buffy Season 8. It's a great little handout and I hope it'll get the comics some more attention. 4 7/8" x 7 1/2", full color.