It is on my timetable and it is the class people ask me about most sceptically, which is fair, because the name does it no favours.
What happens
You lie on the floor. Someone plays bowls, gongs and other instruments for around an hour. You do not do anything. There are no positions to get right, nothing to keep up with, and nobody is going to correct you.
That is the whole shape of it.
Why it works on people who expect nothing
Sustained tones with no rhythm give your attention nothing to track. Most things you listen to have a structure your brain runs ahead of, predicting the next beat. Take the structure away and that part of your attention has no job, and it tends to stand down.
Whether that counts as meditation, therapy or an hour of lying on a floor listening to something unusual is a question you can settle for yourself afterwards. The hour is the same either way.
What it is not
It is not a treatment. I am not going to tell you it fixes anything, and you should be wary of anybody who does.
It is not silent. Gongs get loud. If loud unpredictable sound is difficult for you, this is worth knowing before you are lying down in the dark.
It is not a nap, although a fair number of people fall asleep and I do not mind at all. Snoring is a normal event in this class.
Practical
Wear something you can lie still in for an hour. You will get colder than you expect doing nothing on a floor, so bring a layer. Arrive on time, because walking in halfway through is more disruptive here than in any other class on the timetable.
If you have never done one and you are curious rather than convinced, that is the right attitude to bring me. In my experience curious people get more out of it than believers do.