Again, Rick and Morty season 3 has yet to have any premiere date announced so we can figure out what we have to do to kill time in between now and then.
However, one of those things could be getting a free Rick and Morty game that is not unlike Pokemon called Pocket Mortys.
It might not kill all the time between this moment and the premiere of season 3, but you could always just rewatch the first two season of Rick and Morty.