Tonight is the best night of the year to watch this movie, which I've covered numerous times. I had a chance to dig into every nook of the Blu-ray with the exception of the commentary by writer/director Mike Dougherty. The movie itself is more one to own than rent once a year, and the extras are all substantive enough that one can expect not to see a double dip.
Starting things out is How Did Many of Our Scary Traditions Start? [27:00], which covers the origins of Halloween and how society has stifled or stigmatized so many things. Brian Cox narrates it, and everyone from the director & Bryan Singer to some of the actors to experts and authors chime in. There are 9 Additional Scenes [16:50], which are a mixture of deleted, alternate takes, and extended versions of existing scenes. Trick R Treat: Season's Greetings is an original animated short also directed by Dougherty. Both the excised material and the short feature optional commentary by the writer/director. Rounding things out are a visual effects comparison featurette for the school bus sequence and a Digital Copy. Vote with your wallet on titles like this one. Keeping it difficult to find in stores (online and off) is the best way to send studios a message regarding what you'll spend money on.
The Blu-ray is $22.99 and the DVD is $15.99 at Amazon. They were released back on October 6th, and have both been hard to find in brick & mortar shops.