The ASCENT security teaching lab provides both graduate students and undergraduate students at the University of Texas at Arlington with an opportunity to get hands-on education in both attack and defense. We developed the lab over a two-year period and have learned valuable lessons from its development and use by students. In this article, we examine the design of the lab infrastructure and the use of laptops, the design of exercises, the role of virtualization, and the use of capture the flag exercises. We also discuss the use of our labs in classes conducted at a large software company in India.