Astronomy Labs by McCrady and Rice are absolutely essential for my Introduction to Astronomy course. Though I love getting the students out under the stars and using telescopes, all too often the weather doesn't cooperate! These labs are well designed to explore important astrophysical concepts using the most basic materials and tie in very closely to the course material we cover during the day. Each exercise is designed to take a student through a series of concepts, and its step-by-step framework makes it easy to follow along, but challenging enough to address students' preconceptions. Some of the labs feature simulations that can be found for free online, and those are wonderful in our new smart classroom with shared big screens. You can pick and choose which labs to include to match your curriculum, and it saves the students money at the bookstore. I haven't yet broken the exercises into smaller chunks for active learning in our short classes, but I look forward to trying that in the future.