This lovely offering from the MIT OpenCourseWare project takes interested parties through the world of biology via course readings, discussion questions, assignments, and exams. The topics cover genetics, cell biology, molecular biology, developmental biology, and evolution. The Study Terms section is quite useful, as it covers a host of useful terms from cell signaling, immunology, cancer biology, and genetics. Moving on, the recitations are worth a look as they offer lecture notes in a succinct and learned fashion. It's worth noting that visitors can download each set of activities separately or they can also use the Download Course Materials area to download everything at once.