These virtual labs from the Howard Hughes Medical Institute allow students to experience laboratory procedures as if they were a professional scientist. Students can isolate and analyze bacterial DNA sequences, examine cardiac patients, dissect a leech, or diagnose diseases by detecting the presence of antibodies. These virtual labs include animated steps that must be performed, along with textual instructions and explanations so that students understand not only what they are doing, but also why they are doing it. This is an extensive Web site that offers a lot to learn, and a chance to have fun in the process.