In a nearby park across the road from the old town, there will be live traditional music being performed on stage. There are also huge bazaars set up that sell bull-run related clothes, crafts, food, lots of churros, sandwiches and nick-nacks.
In the mornings you can see the 'Giant-head Parade'.
Throughout the day when you walk through the neighbouring streets of where all the excitement is, you'll see various street performers.
10:00pm Every night of San Fermin festival, you'll find a person dressed in a big bull costume with fireworks spraying and popping from it for at least 10 minutes. It runs down Santo Domingo and down Mercaderes back and forth. It is meant for the children, so they have an opportunity to take part in a bull run. It is unsafe. An adult showed me how some of the sparks burned right through his sweater. Now imagine a shower of those sparks hitting you or your kid's skin. I do recommend going to see it, but stay further back in the crowds so the bull doesn't run near you.
11:00pm Every night of the San Fermin festival, there are fireworks over the Citadel. They last about 20 minutes. Take a light jacket.
At the beginning and end of the festival, there are performances in the bull ring. The one at the beginning of the festival features professionals jumping over and merely escaping bulls with no defense. The second one at the end of the festival features teams of 2 trying to place rings on the horns of young bulls as they're being charged. I have not noted dates because it changes every year, but look out for the posters. It's just about 15 euros per person and it's general seating (sit anywhere).