Everybody likes to be remembered on their birthdays and that's why they are a pinging staple. I have birthdays logged at the top of my Outlook schedule so I can call or email that day when I have a few moments. Birthdays are a great time to let people know that you care about their success. Here's an email I sent one of my best employees on his birthday:
Take a deep breath today and really ask what you want to feel like one year from now. What do you want to be doing, etc. Then, make a commitment to get there and tap into the resources who care about you like me and others in the office and outside and those you know. The point is let's make this year one when you breathe easier and spring out of bed in the am. to do what you do! Happy Birthday.