A question about the name of an instrumental classical piece of music.?

There is a piece of music that I heard a while ago and really loved but I cannot remember the name. I have been trying to find the performance I originally heard it at but to no avail. So I am hoping that some one here might be able to help me. I originally just went about my life but this particular piece of music has recently started to pop into my mind and I would really love to listen to it again but I can not find it.

The performance was by the Orchestra at Temple Square several years ago, but I am not so much interested in finding that as I am the name of the particular piece.

As I said above I do not know the name of it but the piece, when played in its entirety is a little long (I think about 15 minutes but I am not sure). When I first heard it performed the director said that everyone had heard this particular piece and at first laughed at the idea (because at the time I had not listed to much classical music). I do not remember where I had heard it from but I relay that bit in hopes that it will help some one identify it.

The piece repeats the same short beat over and over through its entirety. When it first starts off it has one instrument that is playing the simple beat but then starts to slowly add more and more instruments until it eventually involves the entire Orchestra. I remember that it was written a long time ago but cannot remember the person who wrote it.

I am sure that it would be somewhere on Youtube, but with how little I remember about the piece it seems next to impossible for me to find it. So if you think you know what the name of this particular piece is if you could give e a link on Youtube that would be really helpful for me being sure you have the right one. If you happen to know exactly what I am talking about (if that is possible) then just the name of the piece and perhaps its composer would be fine. I would not be surprised if I were to recognize it when I see the name but I am not sure.

Thank you in advance for your efforts.