...back in London I participated several times in privately organized dinners with a similar setup: The hosts (German couple) would invite a small group of 6-8 people from disparate backgrounds (film makers, architects, bankers, scientists, artists, surgeons, etc.), cook fantastic multi-course dinners for them and then each of us guests was giving a 15-20 min presentation about our work, which was then discussed until the early morning hours... These evenings were some of the most intellectually & culturally enriching experiences I've ever had!
For many years, another friend used to run regular pub nights in Hackney, literally called The Enlightment Club. This was more of an ad-hoc social event, with open invitation and more what we'd call a "Stammtisch" here, but with discussion of vaguely enlightenment topics actively encouraged (i.e. those I also listed in my OP above)...