This list view shows Important Dates for each member.  Dates that are in the current month are highlighted in Red.  

Now once a month, or at whatever interval you you want, just highlight the members in the list with a birthday during the month and you can use the Mail Merge feature to sent a personalized letter to each member with a birthday.

When you select Birthday Letter the letter shown below will be ready to send. You can customize this mail merge template to your liking, or clone and edit a copy of the letter.

You can also filter on the wedding date, then right click the column heading and choose to output an anniversary letter.

The provided mail merge template will produce a customized letter like the one below.