Computer science faculty must attract and retain students by offering innovative courses that spark student interest, yet still teach core, computer science concepts. These efforts have become particularly important as computer science enrollments have declined, thus increasing concerns for attracting and retaining students. We describe an innovative course that leverages students' interest in computer security issues to attract and retain technically-oriented students. Our initial vision was to offer a course covering computer viruses-a subject that even a novice computer user has some familiarity. To avoid the controversy associated with teaching students how to write malicious software, we focused the course on techniques for defending against viruses, so we named the course Defense Against the Dark Arts. In teaching the course, we have found the subject matter provides an engaging way to introduce and reinforce many important computer science concepts that other courses often cover, most particularly, the traditional compiler course. We have taught the course three times at two separate institutions, with a third school soon to follow. The course has been well received by students-completely filling each semester with enrollments that are four to five times greater than the compiler course. Furthermore, student surveys indicate that the course raises students' awareness of computer security while introducing students to important program translation and analysis concepts.