Bakerella has a great method if making cups and bowls out of chocolate. Just inflate a balloon, dip it in molten chocolate, and let it cool. Once you remove the balloon, you are left with an edible bowl that is great for serving desserts in. Each one comes out unique and not looking like it came out of some mass produced mold. You can decide what size and shape you want by what kind of balloon you use and how much you inflate it. It even makes its own little stand as the chocolate runs to the bottom.

You can even make other shapes. Amazon has a bunch of different balloons, like these:

Doughnut shaped balloons

Skinny ones for tall cups