Best alternative to Facebook events? (For planning get-togethers with friends)

I'm looking for the best tool for planning events with friends thats not named Facebook.. Hopefully it will allows people to RSVP, get updates and maybe even chat. Ideally they wont have to create account on the platform. Even more ideal would be if they can interact all via SMS if desired (RSVP, get updates and reminders, etc). Ideally it won't cost anything or have a very generous free tier. I've looked at options like guestboard.co and Google Calendar. Who has some good options out there??