DAVID MALAN: Hello, world. My name is David Malan, and I teach CS50, which is Harvard University's Introduction to Computer Science for students in college and beyond. For 15 years now, Scratch has been the very first language that we introduce to students, most of whom have never programmed before. 

And I myself had the good fortune of meeting Scratch even before then, when Scratch was just a little beta. I was a graduate student in Professor Mitchel Resnick's course at MIT's Media Lab. And we had an opportunity to try out an early version of Scratch. And I spent hours making my very own first project, "Oscar Time." 

Since then it has been such a privilege to watch Scratch grow and inspire so many students around the world, younger and older. It is extraordinary what Professor Resnick, John Maloney, Lifelong Kindergarten, the Scratch Foundation, and so many of Scratch's team members, past and present, have accomplished. Indeed, education around the world is the better for it. 

On behalf of CS50's whole team and thousands of CS50 alumni around the world who have learned how to program because of you, happiest of birthdays Scratch.