It is the 50th edition of the Carnival of Mathematics, celebrating over two years of Mathematics Carnivals! This edition is hosted by John D. Cook of The Endeavor and instead of the expected commentary on the number 50, it focuses on the letter L in mathematics. This carnival also stood out in that John used a bunch of pictures to illustrate the posts. All in all, a great Carnival!
The Big L: The 50th Carnival of Mathematics