There's only one thing I like more than Halloween and its the Day of the Dead. San Francisco celebrates this festival in style - at night, candle lit, with processions to the beat of carnival drums. I find it exciting, spiritual, emotional and largely authentic. People construct elaborate altars in honor of their dead friends and relatives. For a moment you get to share in that person's loss and learn a little about the people who are no longer around through the relics and photos that decorate the altar - bottles of whiskey and cigarettes, wedding photos, a child's shoe, a letter from mother to daughter. It's moving and atmospheric.
I also like this festival because it's Mexican - and that in itself makes it cool. The Marigold project organizes this event and raises money every year - they were a bit down on funds last time I looked :(
Here are some photos