The Account Director who I work for in my day job asked me how to delete old Calendar appointments in Outlook 2003 as he had a load with attachments taking up GB’s of space. As we’re tightly controlled by our support organisation to have quite limited amounts of mail server space he was keen to delete the old appointments.
To my chagrin the Sales Director beat me to it, I had thought there was an automated option but it turns out that you need to navigate to your Calendar and click:
View | Current View | All Appointments
Add a size column using field chooser (right-click an existing column, select field chooser and drag Size to the column position you want).
You can then view all your previous Calendar appointments by size, end date etc. in order to bulk select which ones are to be deleted. Outlook rather helpfully segregates the recurring appointments so that you don’t keen too keen with the delete key.