My lab at MIT publishes a calendar of events on its website. Lab staff can use the site to enter information about talks, seminars, and special events. Lab members can even sign up to get the day's announcements sent to them by e-mail. When I see a talk that looks interesting, I copy the announcement's text and paste it into my computer's calendar.

The registrar's office at MIT publishes the institute's academic calendar. This calendar tracks official events, such as the start of classes, institute vacations, and thesis deadlines for grad students. At the beginning of the school year, I spent half an hour entering these dates into my computer as well.