that weekend is the (in)famous COMFEST, (comfest.org) a large open air community festival in goodale park. sun, rain, music, food, crafts, political discourse of ALL types. it's also columbus pride weekend (stonewallcolumbus.org).
while both of these events are not specifically dog related, lots of dogs will be at both events. i'm pretty sure columbus mounted police will also be at both events(sorta horse related) and on sunday afternoon you can meet me and some of my fur crew. i will check for others as well.