The team at SQLSkills does a quiz on twitter every Wednesday and if you are not already participating in them I highly recommend that you do. I have only ever answered one question correctly and that was only because the answer was in a previous question. Even though I have not really answered any of the questions correctly I still attend the quiz and I learn a lot every week. They are usually 10 questions but they are tough and they always provide the correct answer and they usually provide a link to blogs and or Books Online that provide the detail about the answer. So I would start following #sqlskills if you are not already and take advantage of this fun way that they are handing out free knowledge.
Hope to see you on twitter answering the questions.
And thanks to all of the SQLSkills team for doing this for the community. I know I and many others appreciate it.