Consider it Free Comic Book Day Part 2. This year on Halloween, Diamond and select comics publishers will be distributing free, specially designed comic books. For the past few years, a small selection of mini comics have been distributed on Halloween, but this is the first year that a larger selection of regular-sized comics will be made available.
For this year's inaugural event, IDW is making available a special Halloween variant of last year's TMNT #1 issue. It seems that the only difference this book has is an orangish-colored cover.
Make sure to ask your local comic shop to get it for you!