In addition to the various socials and Discord servers we post on, SLURM distributes event invites via the physical mail and via our e-mail list.
Catch one of the organizers IRL (like at a SLURM event) and we can give you a paper to sign up for our actual mailing list! For this list, we hand-typeset (out of lead movable type, mostly from Skyline Type Foundry in Arizona) and hand-print half-page invites and send them out to you! I rarely get things I actually want in the letter mail, so I want to be that joy for someone else.