Does anyone know the Boston Celtics song with bagpipes in it?

I was at the New Kids on the Block & Backstreet Boys concert last week in Connecticut and at the end of the show, they paid tribute to the Boston Celtics. They played a song that had bagpipes in it, and I know it's a popular song among the Celtics and the Bruins. The problem is that I have no idea what it's name is, or how to find it. Does anyone know anything about it? I'd appreciate it!