Today is December 1st and that means you can open the first door of your advent calender! :) The company I work for also has an advent calender. Every day from today till the 24th a new blog post will be published on our company's blog blog.mayflower.de. Some posts will be in german, some in english.
Again this year, there's also phpadvent.org with new articles about topics around PHP every day.
Have fun! :)