I arrived in Cusco one day before that big celebration and so I could join :) what a coincidence! Unfortunately I found out the tickets are sold out and anyway quite expensive - $90! But lucky me somebody didn't wanted to go so I got one for free. To be honest it is expensive but while sitting in the first row watching the celebration with all these traditional dances its so worth it. They even give you a DVD, a program but only Spanish translation and a little radio receiver for English translation but that didn't work. If you are lucky and be there its a good thing to see! never seen a bigger traditional celebration!