I wound up making these sort of accidentally because I had extra Oreo cupcake filling, and a few people on Twitter asked for the recipe, and seriously, SO EASY.
1 package Oreos
1 block (8 oz) regular cream cheese
Colored sugar or sprinkles for decoration
1. Take out the cream cheese an hour or two in advance to let it soften.
2. Put the Oreos in a food processor and process until they're fairly even crumbs.
3. Dump out into a bowl, add cream cheese, and mix. (It's probably easiest to just use your hands.)
4. Roll the mixture into balls about 3/4" in diameter, and roll each ball in sugar, sprinkles, or other decorations.
5. Keep in the refrigerator until you're ready to serve!