Spent a bit of time today putting some motorsports events into my Google Calendar Account and spread them across different calendars to be able to share them. So, if you want to import them into your own cal, here are the links. The entries contain full GP names, cities, local time start, UTC start and number of laps.
F1:
http://www.google.com/calendar/ical/...blic/basic.ics
Other series:
ALMS:
http://www.google.com/calendar/ical/...blic/basic.ics
LMS:
http://www.google.com/calendar/ical/...blic/basic.ics
Le Mans:
http://www.google.com/calendar/ical/...blic/basic.ics
FIA GT:
http://www.google.com/calendar/ical/...blic/basic.ics
Also, if you are using iGoogle Desktop and have the GCal widget, remember that you have to set the new calendars there to be visible.