Some people don't decorate much for the holidays, because how much can you spruce up a two-bedroom apartment that's mostly held together with cat hair? For those desirous of holiday beauty, any number of tours in town feature beautifully decorated homes. Perhaps the loveliest among them is the Lafayette Square Parlor Tour, which stars eleven homes in the city's grandest neighborhood that have been properly decked out for the season. Their owners open the doors today from 10 a.m. to 5 p.m. to welcome admirers. Interested parties should meet at Park House (Mississippi and Lafayette avenues; www.lafayettesquare.org), where you'll pay for your tickets ($20 to $25) and tour book. If you want to make the tour in style, free carriage rides are offered; there's also a holiday market and kids' crafts (from 1 to 3 p.m.).