Lights

Christmas wouldn't be without checking out the lights in the neighborhood. With the Internet, the World becomes our neighborhood.
The White House Christmas Tree was lit Dec. 4. This clip is from CBS News They also have a series of photos of other Christmas Trees to the right of the article.

I have been looking at several resources on the history of Christmas and the History Channel's web pages on Christmas are the most interesting and succinct.

For more divergent opinions, try Christmas in cyberspace.
and if you want to decorate a tree, try these

The Christmas Tree Game

Build a Christmas tree (Requires Shockwave)