Most interesting phenomena in natural and social systems include constant transitions and oscillations among their various phases.  Wars, companies, societies, markets, and humans rarely stay in a stable, predictable state for long.  Randomness, power laws, and human behavior ensure that the future is both unknown and challenging.  How do events unfold?  When do they take hold?  Why do some initial events cause an avalanche while others do not?  What characterizes these events?  What are the thresholds that differentiate a sea change from a non-event?