Make your activities and planned activities show up in your own calendar (Exchange, iCal, iOS, Google Cal) by making the information CalDAV compatible.
Ladies and gentlemen, Garmin has heard our pleas for calendar export functionality: http://connect.garmin.com/help/whatsnew. As of this morning (after my earlier post), one can export the next 30 days of workouts into an external calendar (e.g. Outlook, Google Calendar, etc.) I tried it and it works. Thanks for listening, Garmin.