It's family fun night at Zenodotus and what's more fun for those who believe in Santa than the Norad Tracker. This year they have added an entire North Pole village that acts as a countdown (which I wish I had known about before now) which is full of educational activities. I like the way in recent years they have teamed with Google Earth to give a geography lesson of sorts.
Admittedly, I am not as familiar with Hanukkah, but I need look no further than Hanukkahfun.net to find a great deal of great information and fun activities.
I haven't found anything for Kwanzaa yet. So, if you know of something please add a comment. Also, feel free to share any other holiday sites you may know about!