The Festival of St. John in Florence

Yes - it made the Piazza della Signoria an even more exciting place to be than usual.

There is also a 10k race the Saturday before which is run at night and it is great. Such a festive atmosphere after the run. I enjoyed the fireworks from one of bridges along with thousands of other people.

The other amazing event is the Calcio Fiorentino - the wildest "soccer" match in the world. It is part soccer, part wrestling, part boxing and part madness!
We were in Florence for the opening parade and first games at the beginning of June and it was wild. A wonderful mix of sport and art and community. The event finishes with the final game on June 24th. The whole town seems to show up for games which are held on a temporary pitch set up at Piazza Santa Croce in front of the church.

I didn't get to see the Calcio IRL, but peeked in the doorway of a bar where they were showing it on TV. The players were in Medieval costume, while the referees looked totally modern.

If you can fit it in your schedule, why not. I try to be in Florence for that day every year, including this year. The fireworks are great (best views are from the Lungarni half way between Ponte alle Grazie and Ponte San Niccolo).

Regarding the calcio Storico, it can get violent. As mentioned, on the pitch, it is a mix of rugby, wrestling, and kick boxing. On the stands, it's just kick boxing brawls. There are 4 teams representing the 4 original quarters of Florence (the Reds, the Greens, the Whites, the Azzurri, or light blue). The final is nearly always between the whites and the blues. If you attend, avoid those colors, or the opposite fans might think you are a fan and beat you up, just for the heck of it. Wearing violet purple (the colors of the Fiorentina serie A soccer team) will always win you friends in Florence, no matter which quarter they are from.

Yes! We were there for my son's 16th birthday last year, and we are going again next year for his 18th. We started the morning watching the parade near the Duomo and then climbing the Giotto's Campanile Bell Tower. Earlier is definitely better, because when we exited, there was a huge line.
There was a big crowd around the Duomo, and we people watched for a long time. We went back to our apartment during the afternoon and watched the soccer/rugby match on the tv. Whoa. Then we went to eat a bite, and went to see the David. Ran into Derek Jeter there, which was kind of cool. After that, we found a lovely little restaurant near our apartment and had the most delicious birthday dinner for our boy. Coming back to the apartment, we climbed to the top of our windows and saw the most amazing fireworks show. Can't wait to repeat the experience next year. The energy in that city is amazing that day.

Oh, and Richard, I'm in Martinez! Small world!

Still on the fence about changing our plans. I have a week at an Agritourismo near Sienna that I would have to cut into. The festival does sound like a good time.