Simple incidents are easy to handle for trained cybersecurity experts. But when cyber-attacks take on a larger scope, preparedness is the only way to limit damage and recover promptly; in other words, to having cyber resilience. And preparedness only comes from exercising. Cyber exercises put cybersecurity staff through a set of simulated cyber incidents to demonstrate, train, practice, assess, and/or certify participants. They can significantly increase proficiency and resilience, as well as validate critical but seldom-used operating procedures and business recovery processes. But not all exercises are equal; while off-the-shelf exercises can easily help improve individual technical skills, only customized cyber exercises can help with the bigger picture issues such as teamwork, public media engagement, legal issues, external stakeholder engagement, communications with management and senior executives, and incident management under pressure. This presentation will describe some of the key aspects of planning and executing highly-successful custom cyber exercises.