Combine pulverized cookie crumbs and cream cheese, mixing together with a wooden spoon to distribute as evenly as possible. When no longer able to incorporate with a spoon, with your hands squeeze mixture together to bind. Form mixture into 24 1-inch balls and place on a wax paper lined baking sheet. Freeze for 1 hour.
In the meantime, melt the dark chocolate bark or melts in a double boiler. Using a toothpick, dip truffles completely into melted dark chocolate and twirl to allow the excess to drip off. Place back on lined baking sheet and, if desired, sprinkle with nonpareils before chocolate sets, otherwise see green drizzle below. Refrigerate until firm.
If drizzling with the melted green-colored chocolate, melt in double boiler. Color melted white chocolate with 2 drops of green food coloring. Drizzle over the top cooled truffles with a back-and-forth decorative pattern.