I'm not sure if it's an actual holiday but I think my favorite holiday of the year would have to be Advent. In fact, I love it so much I'm hosting a contest for it here.
I could tell you that I love advent because the entire church is decorated in pink and purple. While the readings can be ominous the music is upbeat. I could tell you I love Advent because it is the one time of the year I can push my entire home into a blur of pink and purple without listening to my husband complain. All of this would be true. But the thing I really love about Advent is the anticipation--the anxiously waiting. The way the story unfolds.
Most holidays last a day. They are the event. Family comes or family leaves. There are customs to be shuffled through without ever wondering why the became customs in the first place. We get through the day. It ends. It's over until next year, because, well, tomorrow is just another day. But Advent is not the event. It's the coming of an event. It's the preparation for the event. It's the well manicured tension of a complex plot building to a climax. It's a month long. Each week a new candle lit until it unfolds, dissovles. Advent fades into Christmas, the climax. In a lot of ways Advent is a writer's dream holiday not only blanketed in often beautiful language but color and ceremony.