The Advent of Data is a traditional advent calendar. The main difference is that this time each day you will get a data article rather than a sweet or a chocolate. Even if we can maybe consider data articles like sweets they don't give cavities.
This year we have 24 awesome authors producing an exclusive content for the occasion. Everything is free and if you like it you can even subscribe to get your daily email notifying new post.
To get this idea I've been largely inspired by a French initiative called 24joursdeweb that is doing the same since 2012 in the web/frontend domain. The homepage may also look similar.