Fourth Avenue
If you like the idea of browsing hundreds of local and mom-and-pop businesses all in one place while having your pick from all kinds of fast and greasy food vendors, the Fourth Avenue Street Fair might just be your jam. And if that doesn't sound enticing enough, did I mention you can also drink beer while you're doing it—like on the street? During the winter fair, get all your holiday shopping done in one spot, and at the spring fair, day drink outside before it gets too hot to do so.
Runners up:
2. All Souls Procession
3. Tucson Festival of Books