Scientists have to learn new experimental techniques all the time. However, being given a protocol from a labmate or taking your sample over to the core facility does not actually endow you with any background knowledge related to that technique. When it comes to flow cytometry—a technique that is commonly employed to count and isolate specific populations of cells—the BD Biosciences website contains an excellent interactive resource that actually teaches researchers about the technique they are about to employ. The interactive course includes seven modules as follows: overview (an introduction to flow cytometry), fluidics, optics, electronics, optical measurements, data analysis, and sorting. While optimized for particular web browsers, I found the tutorial to run smoothly even with a “suboptimal” browser. Very informative and engaging, this website is a must-visit for anyone new to flow cytometry.