Hi,
For the holidays etc you would probably be best to use a marketing tool like click dimensions (or attempt to use the out-of-box marketing features). This would allow you to send out a bulk email etc to all your contacts, or selected contacts based
on marketing lists.
For the Birthdays, there is one option of creating a hidden 'Next Birthday' field to capture the date of the contacts next birthday (eg if birthdate is 10/06/1984, the Next Birthday would be 10/06/2013). You would need some javascript or a plugin to populate
this date when it is initially set.
You could then build a workflow to run when the Next Birthday is entered (and also as a child workflow). This workflow would wait until the next birthday, send the emails, update the next birthday to increment by 1 year, and then call the same workflow again.
You can read more about this birthday workflow here:
http://blogs.msdn.com/b/crm/archive/2008/01/08/part-1-happy-birthday-via-workflow-using-client-side-scripting.aspx
Hope that helps
Paul
