If Christmas and New Year's Eve parties have to be cancelled this year, perhaps it's time to remember an old rule: It doesn't take a special occasion to drink premium wine. The wine itself becomes the occasion. This is no less true for the sparkling versions than it is for still wine, at least when it's really good. And what's better than having your mellow mood illuminated by a decent champagne, the finest spumante, vintner's sparkling wine or cava? This also works in the smallest circle, in an emergency even alone.