Chill a 9-inch loaf pan or glass container in the freezer.
Add the heavy cream, powdered sugar and vanilla extract to the bowl of an electric mixer. Using a whisk attachment, whip until stiff. Fold in the condensed milk. Divide the mixture between 2 large bowls.
To one of the bowls, add the cocoa powder, melted semisweet chocolate and chocolate chips, then fold into the whipped cream.
To the second bowl of whipped cream, add the melted white chocolate and chopped white chocolate, then fold in.
Layer the different cream bases into the chilled loaf pan a couple spoonfuls at a time. (There is no rhyme or reason when layering; you want it to be imperfect.) Once all of the base has been added to the pan, swirl the two using a skewer or butter knife. Sprinkle an assortment of sprinkles over the top and wrap lightly with plastic wrap. Freeze overnight.
When ready to serve, scoop into individual glasses and top with additional sprinkles.