I quote from the Food Lover's Companion:
From the Nahuatl molli , meaning "concoction," mole is a rich, dark, reddish-brown sauce usually served with poultry. There are many variations of this spicy Mexican specialty, usually depending on what's in the cook's kitchen. Generally, mole is a smooth, cooked blend of onion, garlic, several varieties of chiles, ground seeds (such as sesame seeds or pumpkin seeds — known as pepitas ) and a small amount of Mexican chocolate, its best-known ingredient. (Some Americanized mole recipes use bitter chocolate.) The chocolate contributes richness to the sauce without adding overt sweetness.
Love mole sauce but, for some reason, have never made it. There are many recipes on the web that vary in complexity and authenticity.
Generally prefer turkey mole to the one with chicken, but any mole is good.
And I am sure someone will drop by with a favoirte recipe.