I used to be able to see friends' birthdays in the right panel of my homepage. But now all I get is the minifeed and ads. And this isn't because none of my friends are celebrating today; If I click events I see that 3 friends were born on this day some years ago.
It appears I am not the only user (still) experiencing this issue. Here's a not very helpful help thread at Facebook.
Why did birthdays get buried?
Update (6/21): Birthdays are back for me. This problem seems to have corrected itself.