Want to take a course at MIT? Now you can. Academic Earth is still in the infancy stages, with only a smatterings of offerings, but it is easy to imagine a time when thousands of complete college courses will be available here. For now, take yourself back to your college days and learn something new at the same time by clicking on a course of interest and listening to a lecture (or a full series of lectures) by a well respected professor. Who knows, you might even find something worth sharing with your students.