My favourite folk club is in my husbands home town of Beverley. When his mother was ill and we spent a lot of time there it was a lifeline.
Used to meet in a rectangular room upstairs with tables along the sides and an open fire at the end where you stood to sing or play.
It was more often a singers/musicians night with Richard in charge to see that everyone got a chance if they wanted. The standard was generally very high, but the feel was inclusive so you could have a go (or just join in any chorus that happened). The members had very varied styles.
Sometimes, to encourage people learning new songs, Richard put on a theme night, but was'nt too strict about it. Then Bill would do something daft, like the "Sea songs night" when he sang "Just a shanty in old Shanty Town"
They had a guest night once in 3 or 4. The floor singers for that were the best of the members.
The room was good to sing in, so no amplification needed, and people paid attention. Nice friendly club.
Due to changes in music licencing they've moved and are now called "Not the White horse Club". Don't know if it's changed the atmosphere, but I guess the members are as good.

At home I usually go to Folk Dance Clubs, which are different beasts. What Greg said about age applies to them even more.

And there's a pub in Audlem that holds my favourite music session.
Sessions don't usually have an MC, you start a tune or song when you feel like it. Some sessions are expert, and must be quite exhilarating if you are good enough.
At the Shroppie Fly, although they are good musicians they play things lots of times through and not too fast, there are songs you can play along to, and everyone is encouraged by the friendly members. It's different every time you go, according to who's there.