Active learning refers to techniques where students participate actively in a lesson rather than just listening to a lecture. It involves students discovering, processing, applying, and presenting information. Examples of individual active learning exercises include keeping a daily journal, participating in reading quizzes, asking for clarification, and identifying ideas. Active learning techniques for groups can include discussions, comparing notes, and evaluating another student's work. The document also provides examples of active learning techniques for gifted learners, junior high students, and reasons for using active learning techniques in the classroom.