Crushed Oreos add a bit of magic to homemade ice cream, brownies, cookies, piecrusts, pancakes and candy. They don't come crushed, though, so all that work is up to you. The best way to crush them depends on how you plan to use them.
If you have a food processor, it'll make quick work of pulverizing your sandwich cookies. Be aware, though, you will end up with fairly fine crumbles -- suitable for a piecrust or sprinkling over hot chocolate. Even if you try the pulse feature for more irregular crumbles, you will still end up with relatively fine crumbs. If you prefer uneven chunks of the cookies for your recipe, the food processor may be too industrial for you.
This method requires a bit more physical effort on your part, but yields haphazardly crushed Oreos perfect for adding to ice cream or pudding. Place the cookies in a zip-top plastic bag and seal. Use a bag that's large enough to hold the cookies with room to spare -- usually a gallon size or larger. Hold onto the sealed edge of the bag to ensure it doesn't pop open as you lightly bang on the bagged cookies with a rolling pin, pan, rubber mallet or sturdy glass. You can use as much force as is needed to get the texture you want for the cookie crumbles.