Sunday Assembly
A ‘Sunday Assembly’ would be more congruent with the ethos of Edgeryders than a ‘Samhain’
I would be especially concerned not to give any false impressions of Edgeryders, LotE or the unMonastery…something ‘spiritual’ at very short notice…with candles, ceremonies etc is likely to be misinterpreted in the absence of a lot of pre-briefing …
Personally, I prefer to celebrate my/our awareness of the Earth’s wobbles and our limited understanding of it’s beauty in a rational and forward looking style than one founded in superstition (speaking as a speaker of the original language of the ‘Samhain’… 
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