ComFest
Web: comfest.com
You won't find a better venue for voyeurism than ComFest. Practically every sort of person turns out to sip beer from souvenir mugs, discover new local music and socialize in the sun (and, of course, dodge the nearly annual downpour). Seeing stiff-necked suburban yuppies unwinding next to body-painting hippies is one of the distinct pleasures of this cultural kaleidoscope.
Runners-up: Ohio State Fair, Gallery Hop