Why is there Something Instead of Nothing?

At its core, physics is a field devoted to solving fundamental questions. These puzzles have inspired and tormented countless physicists throughout the ages, and the best minds are still busy at work pinning down the details through both active research and philosophizing beside the department coffee machine. What was the universe like in the beginning? What makes up all the stuff we see around us? Why is there something instead of nothing, and why is so much of it crammed onto my desk?