Planning on visiting some friends next month. I'm sure they'll show us the best of that city, but does anyone here know of unmisseable things to see or do?

Plaza del Castillo is the place to chill for a beer or three, to see and be seen.

You cannot visit Pamplons and not see Plaza de Toros

We spent about six months there, off and on, a few years back (Pamplona is famous for its hospitals). Most of the city is 'modern' with a beautiful casco viejo worth getting to know. Outside of the famous fiestas in early July, there are few foreigners. People are friendly, although 'reserved' (at least if you are used to Andalucía). It's worth taking a car to see surrounding area - beautiful castles and loads of history. Check the tourist office.