As a music teacher, I don't have the time or the energy to keep track of the 400+ birthdays in my school. Luckily, we have Youtube. If a student comes to my room with a Happy Birthday sticker from their teacher, or if they tell me about their birthday (sometimes it happens on a non-music class day), I will play a short Happy Birthday video. I try to keep it under 1 minute, and as with most Youtube videos, you gotta watch and mute your projector screen before the links that pop up at the end.
Jack Black is a favorite with the kids. Gotta love those silly faces.
Cute puppet sings "Happy Birthday"
Don't cut this one off too soon, these singing dogs aren't done yet!
Shabbe do we ya!!!
And my personal favorite: