A message was left. It's a service that calls people to wish them a happy birthday. This one was from our orthodontist leaving a message for our daughter. Totally not a big deal.
I'm a programmer, too. I was thinking it could just be a nice service, or it could be someone trying to determine if someone will actually answer the phone. Another method of finding out if the phone number can be used for other... things.
I got a call on my cell phone from this number today. I didn't answer (usually don't answer when I don't recognize the number), and it left me a VM with a recorded "Happy Birthday" song. Said it was from Jackson Hewitt Tax Service. Today is my birthday, and I did have my taxes done at Jackson Hewitt once (although it's been a couple of years ago, and I no longer use them).