If I were to be accurate, I'd have to check off theater, concert, dance, and live music as the appropriate themes for this tip. For more than twenty years, each June and July, Ravenna has hosted a cultural extravaganza -- often siting the concerts, plays, operas or ballets in the mosaic-rich basilicas at its disposal so that tourists get an incomparable "two-fer". It has pretty decent provenance, too, having been founded by Riccardo Muti and his wife.
If you're going to be in Ravenna during the early summer months and enjoy culture, do yourself the favor of checking out the Festival offerings. They often perform lesser-known operas, good to know if you're an opera fan.
Dress Code: No special requirements. In this day and age, people go wearing all sorts of attire.