We had one on Yahoo for Ceilidh organisers, but it has been closed down - Yahoo Groups closes From what I remember it was the kind of thing, and easy to use.

there is https://www.proboards.com/ - I know nothing about it, free but suspect it has ads.

Wordpress seems to be, at its origin, a forum medium, but that would involve techy work and maintenance - and webspace that provides it, if you already have such.