Tate Gallery has made an iCalendar feed for their events and exhibitions, which is a useful thing to have if you like the Tate. Go here to subscribe, and their events appear on your calendar.
While I’m on the subject, Kultur Fabric has one too and it works in the same way, only we’re using it to list our favourite London shows along with information about each exhibition, location, hours, and a map of how to get there. New exhibitions are being added all the time as we discover them. If you want to have a look or subscribe, it’s listed under ‘Links’ to the right of this page.