Pull the grapes off the stems and rinse in a colander. Place in a ziplock bag and pour one bottle of champagne over them. Zip it up and let sit in your icebox for 3 hours minimum...overnight is even better. Then, if you're feeling like a pirate, pull half of the grapes out and soak in Sailor Jerry Spiced Rum (or any other booze of your choice).
Let them soak for another few hours or even over night if you prepared well in advance. Roll them in Superfine sugar and serve.