The San Fermín fiestas officially begin at 12 noon, on July 6th - with the much anticipated "chupinaxco" rocket blast at the Town Hall. At this moment, as Hemingway described, and as Michener confirmed, the old city of Pamplona "explodes"!! The first bullrun is at 8am, on July 7th, with bullruns each morning through, and including, the 14th. The San Fermín fiestas officially end at midnight on July 14th, with the "pobre de mí" closing ceremonies at the Town Hall. Be there!!
For some very graphic images of the sanfermines, visit this site: http://www.boston.com/bigpicture/2009/07/the_festival_of_san_fermin_200.html