Package coming late? Someone you forgot? You can still send a beautiful e-card today which will arrive on time. These cards are free.
Best religious cards I found (also has nice religious advent calendar)
Nicest photo cards I found are Apple's icards.
This site has some really cute anime Christmas cards.
Read 'Twas the Night Before Christmas.
Give to charity.
Don't forget to monitor Santa's progress at the Norad Santa Tracker site.
Bake some cookies using recipes from:
AllRecipes.com Christmas cookie countdown advent calendar (also has cake and candy ones)
The Jarmann sisters, whose aunts cooked for Nelson Rockefeller, they say.
The site RazzleDazzleRecipes has some traditional recipes like pistachio cookies.
A bit less traditional, but great for pop culture-lovers are Martha Stewart's favorite cookies. Check out the Green Tea Leaf Shortbread.
Central Valley Christian School has put together a HUGE archive of recipes, essays, and interactive materials. I wouldn't normally recommend a site like this, but it's really well done.