This question is to gather community input on what sorts of posts we should have on the upcoming math.SE blog.
If you have an idea for a type of blog post, post it as an answer below.
Vote up an answer if you would like to see this type of post on the blog.
Do not downvote any answers.
Feel free to edit existing answers to clarify or expound on an idea.
Many suggestions have already been made; I am including these suggestions as answers below.