"Happy birthday! Have a great day!"
Perhaps you're a bit more creative than the above greeting, but even the most clever among us have probably run out of ways to wish friends a happy birthday on Facebook.
Thankfully, an enterprising Reddit user whose handle I do not wish to repeat in this space offered a handy and simple tip: search YouTube for "happy birthday" and your friend's name. You will be surprised by the volume and variety of videos available.
Sure, your friend will be sung happy birthday wishes by a random stranger or group, but I think that's part of the charm. And you might even find a professional in the results; when the day arrives where my daughter is on Facebook, I now know that Florence and the Machine (and a theater full of people) are there to sing her a YouTube happy birthday.