I agree with somedude, its not possible create an event that repeats imbalance specific day ( rather than date ) of a month in the current N9 calendar app. I'm unsure whether this will be a new feature in the pr1.2 planned enhancements. I get round the problem by adding more complex recurring events in (my case) Outlook and syncing with Nokia Suite. MfE is a natural alternative if you use an exchange server or google calendar etc.