Funny. Right at the moment I realize I forgot a friend's birthday, I see this message by LJ:

Have you ever forgotten one of your LJ friends' birthdays and felt really guilty afterward? Well, we've got you covered because LJ birthday reminders are back! (Comment if you remember birthday notifications, because that means you're old skool.)

That's right, every time one of your LJ friends has a birthday coming up, we'll send you an email a few days ahead of time. That will give you plenty of time to plan a surprise party, send them a v-gift, or sing happy birthday to them in a voice post on your journal. You'll look like a hero!

Well, tenzintogden, first of all let me ask you to forgive me: I think that day only one man was on my mind, and it was a Nobel prize ;-)
Second, don't worry: next time I'll receive LJ's notification, so it's the last time I forget :)

Very late happy birthday :)