We'll put this weekend's post up a day early to get things rolling. I have a schtick I do at the beginning of every class where I take a few minutes and let the students ask me any question from auto mechanics to quantum mechanics. When I started the Playground years ago, some former students asked if I'd bring it here. So, as an occasional series of posts, I throw it open. If there was ever a question you just wanted to ask, here's your chance. We'll discuss as many as I can get to next week.