Happy Halloween! Apple has its own Halloween round-up on the App Store here, and I've been rocking most of the same apps I covered a couple of years ago. We've also got a few apps, costumes and interactive books on our Halloween tag page. A search in iTunes for "Halloween" will yield hundreds of apps of varying quality.
I highly recommend Angry Birds Halloween, in both the HD and regular versions, as they deliver all the fun of Angry Birds with new levels, a spooky background and jack-o-lantern
