“Rick and Morty Live Stream” With Dan and Justin – June 29th

The R&M live stream is happening! Will you be there? Or will you stream it? https://t.co/ZTVopZCWsU

— Rick and Morty (@RickandMorty) June 25, 2017

I’m not sure what this is about, but uh… itshappening.gif

Anyway, it seems to be a live event with Dan and Justin, though the in-person tickets are already sold out.
The event page says it will also be live streamed on adultswim.com.
Times:
June 29th.
9 PM ET
6 PM PT

I’d say it’s same to assume this has something to do with season 3.