Marc de Champagne is a brandy made as a by product (pomace) of the Champagne making process by using the discarded seeds and skins. Drink as a liquor or use in cooking.
Marc de Champagne is commonly used as a filling for chocolate truffles.
This can be pretty hard to find. Bevmo.com has carried it in the past but had none the last we checked (June 2014). Check in with the WineSearcher for bottles in your area.
For truffles filled with this brandy, try Sur la Table.