These advent calendars cover topics as diverse as web performance, UX and Perl.
It is the season to be nerdy. Over the last few years, virtual advent calendars for web designers and developers have become increasingly popular. There are many that have come and gone.
In previous years, for example, we had UXmas, an advent calendar for user experience designers; the Adfont Calendar, presented by Fontdeck, which gave away a free web font every day; as well as the MDN Holiday calendar, by the Mozilla Developer Network and built by Christian Heilmann. It provided daily resources "for you to look at, enjoy and even give some editing love".
None of those calendars have been updated for 2015 but all the articles are still online, so if you missed them initially, make sure you take a look. Here are the best ones for this year.
Throughout December 2015, 24 of the world's leading content strategy experts will share their advice and tips on all things content related in this cool advent calendar. Day one begins with Karen McGrane taking about modernising content tools and processes, and we'll also get to hear from Meghan Casey, Gerry McGovern and Ida Aalen this week.
02. 24 Ways
24 Ways is the mother of all advent calendars for web geeks, now in its ninth season. The brains behind 24 ways, Drew McLellan, director and senior developer at edgeofmyseat.com, told us: "It's aimed at designers, developers, copy writers, producers and others who work in whatever capacity to create websites. We cover a whole range of topics from design and development to business matters and inspiration.
"24 ways has been running since 2005. Despite being in a compressed timescale, we publish about the same number of articles each year as A List Apart. The site is very popular, with traffic in the region of 70,000 visitors a day, so the decision to carry on is an easy one. We'll stop when people are no longer excited to read the articles in the lead up to Christmas."
03. 24 Pull Requests
Celebrate the holiday season with 24 Pull Requests, an initiative to encourage developers around the world to send a pull request every day in December up to Christmas.
The project aims to promote open source collaboration during the festive period, with the team behind 24 Pull Requests commenting on the site: "You've been benefiting from the use of open source projects all year. Now is the time to say thanks to the maintainers of those projects, and a little birdy tells me that they love receiving pull requests!"
The Web Performance Calendar, started by Stoyan Stefanov in 2009, is the one for speed geeks.
Stoyan told us: "I modeled it after 24ways.org. The first year in 2009 was mostly me, I wanted to give an overview of the web performance optimisation (WPO) discipline and the self-imposed deadline of an-article-a-day was very effective ABS (or rather AWBS – Anti writer's block system). I only had a few contributions from friends from the industry."
Don't laugh, there's even Perl Advent Calendar! It's been going since 2000 and features a different Perl module each day for the 24 of advent, and an extra module on Christmas day.
It all started, when the London Perl Mongers were having a quiet social drink in the pub. They were talking about online advent calendars and the impracticality of shipping chocolate through your web browser. Mark Fowler then quickly hacked together a calendar and lo and behold it proved very popular.
06. AWS advent
Amazon web services calendar is still a work in progress – more a collection of 24 posts in the build-up to Christmas. Creator Brandon Burton is looking for Amazon Web Services users to author several of the days – head here to find out how.
07. 24 jours de web
Here's one for our French-speaking readers (or those who use Google Translate). Again based on the 24 ways calendar, 24 jours de web is a collaborative website hosted by Rémi Parmentier of HTeuMeuLeu.
And now an advent calendar for German web geeks. Webkrauts are a consortium of German-language web workers, committed to increasing web standards in German-language sites – although their calendar is packed full of transferrable web treats.
As befits the name, Sysadvent is an advent calendar aimed primarily at system administrators. However there's plenty here for developers too.
'It's a Shape Christmas' is a collaboration between Manchester studio Made By Shape and creatives from around the world. As the name suggests, it's a digital calendar themed around Christmas and shapes and allows you to download artwork free on to your iPhone and iPad.
If we missed any calendars that you think should be in this list, please let us know in the comments!