Piccolo cafe is popular among young gay people in Firenze, you'll find here a lot of students , both locals and international ones. It's opened every evening, it's obviously more lively on weekends , can be kind of quiet on week days , especially if you're coming on Mondays and Tuesdays. But, depending on the weather and the city mood, you should find some nice atmosphere the rest of the days. Nice place to go for some drinks and meeting local gay guys, who can be really cute :)