On the centenary of the Bolshevik Revolution the Festival of Lights will take place on Palace Square where that coup started. If you are in SPB on those days you can see the light music installations from 7 till 11 pm. The facade of the General Staff Building will be used as a gigantic screen. Another place of the festival is Cruiser "Aurora" (Petrogradskaya emb.) which announced the beginning of Revolution by giving a blank shot.
Sessions will run every 15 min. (http://www.visit-petersburg.ru/en/event).