The German speaking community is highly decentralized however a common branding is "Einundzwanzig" ("Twentyone").
They developed this Nostr based app
https://zapstore.dev/apps/space.einundzwanzig.meetupwhich helps to find and organize a local meetup.
Among other things it solves one particuar problem: In person P2P Bitcoin trades at a meetup. You build a reputation by visiting meetups and get cryptographic proof by others therefore generating a web of trust.
So it helps the community converging meetspace and cyberspace.
PS: The branding originated off the
@Einundzwanzig podcast initially by
@markusturm and
@Gigi .
PS2: The community map:
https://einundzwanzig.space/meetups/