Here is a list of GH Birthdays & Anniversaries that I've been keeping track of over the last few years:
(exact days may vary from year-to-year, sometimes they fudge it by a day or so, if they remember it at all... )

Jan 17- Mac's Birthday
Jan 17- Emily's Birthday
Jan 17- Jason's "Birthday" from when he "woke up"
Jan 17- Anniversary of Mary Mae's death
Feb 6-  Robert & Holly's Anniversary
Feb 17- Keisha's Birthday
Mar 24- Tony's Birthday
Mar 31- Brenda's Birthday
May 1-  Monica's Birthday
May 18- Anniversary of BJ's Death
June 9- Paige Bowen's Birthday
June 28-Robert & Anna's Anniversary
Aug 3-  Bobbie's Birthday
Aug 5-  Lila & Edward's Anniversary
Aug 7-  LuLu's Birthday
Aug 15- Alan & Monica's Anniversary
Aug 18- Lucas' Birthday
Aug 19- Stone's Birthday
Aug ?-  Stefan's Birthday
Sep 16- Robert Scorpio's Birthday
Sep 17- Katherine's Birthday
Sep 19- Jason's (real) Birthday
Oct 6 - BJ's Birthday
Oct 7 - Ruby's Birthday
Oct 12- Robin's Birthday
Oct 13- Bobbie & Tony's Anniversary
Oct 31- Maxie's Birthday
Nov 4-  Elizabeth's Birthday
Nov 6-  Nikolas's Birthday
Nov 16- Luke & Laura's Anniversary
Nov 21- AJ's Birthday
Nov 29- Anniversary of Stone's Death
Dec 7-  Serena's Birthday
Dec 19- Laura's Birthday
Dec 2?- Michael's Birthday
**************************If anyone has any more Birthdays,
Anniversaries, etc, that you know of, please e-mail me. Thanks!