Advent and holiday calendars

As every year there are several holiday calendars.
The ones I follow this year are:

24 Ways – Web design and development articles and tutorials for advent

MDN Holidays calendar by Chris Heilmann

24 Pull Requests – Giving back little gifts of code for Christmas

25 Days of Making – faberdashery

There are two more in German:

Webkrauts Adventskalender 2013

Hangout Adventskalender