I crumbled the cake in a bowl and mixed in about 3/4 cup of cream cheese frosting. Mix the frosting a little at a time. You don't want it to be too wet, just enough frosting to bind the cake crumbs together. Then I formed little cake balls.
For chocolate, I recommend candy melts or chocolate bark. I made a couple of cake balls with regular chocolate chips and not only was the chocolate a little too thick, but it also took over an hour to set. The candy melts set in less than 10 minutes. I purchased my candy melts at Michaels and they come in a wide variety of colors.
Have you made cake balls? What's your favorite flavor combination?