My wife scoffs at me

and questions why she can remember birthdays better than I can.  The answer is simple.

And when I come up with it, I will let you know.

And this would be a perfect use of Google+... Within Gmail contacts, you can specify dates like birthdays, anniversaries, and so forth. Then Google only needs to provide the capability to mark which dates within your contact for which you'd like to receive a notification and potentially how far in advance you'd like to receive it. In addition, if the contact is within a circle, the marked date would also appear in the stream for that circle.

Actually, another option is if you can tie dates in contacts to your events in your Google calendar. Then the calendar entry can be marked whether it provides you notification or not. Besides improving the social aspect of sharing, Google should focus on making information easier to manage. Duplicating the same information in multiple Google Apps is not desirable.