This blog post by James Rowland Jones on a specific type of deadlock is so interesting that I have to share the link to it. Not only so other people read it, but in case I ever need to find it again in a pinch, I can easily find it on this post. James encountered a very interesting deadlock and provides a really in depth explanation including the use of an undocumented side of locking in SQL Server that you'd be hard pressed to find somewhere else online.
As an additional note, he mentions at the bottom of the blog post an upcoming SQL Server Internals book that he is co-authoring with Christian Bolton, Justin Langford & Brent Ozar with contributions from Cindy Gross and me. I am working on the Waits and Extended Events chapter in this book currently which has been quite a learning experience and has really changed how I look at problems in SQL Server and troubleshoot performance issues personally. More to come on the book when it gets closer to publication.
Apparently Jame's blog post was so interesting it sparked some other posts online as well..