This is a free, all-day food festival at the Botanic Gardens (10th and York) with vendors, samples, and classes. It's not an explicitly vegan event, but it's definitely vegan friendly, and I encourage you to check out the class schedule and register here: http://www.botanicgardens.org/events-exhibits/special-events/food-day.
There look to be some good talks on gardening, food justice, food preservation/fermentation (the last of which is taught by the guy who owns Five Points Fermentation and the Queen Anne B&B).
You can also stick around for a bit and check out the beautiful Gardens, because admission is free that day. Bring people! (Kids, great, dogs, unfortunately not.)
And it's networking!
We might not run into each other, but I hope that you can go for at least part of the day.