I was in Lisbon for a conference last week, and was pleasantly surprised to discover that there is a huge book festival in Lisbon that runs for almost 3 weeks.
I was out for a run and discovered them setting up a huge number of booths along the major park in the center of Lisbon.
I unfortunately did not get to experience the festival directly but as it looks like it's been going on for 85 years, it seems like it's a big deal.