The most well known (and I think long lived) LAN in The Netherlands is Campzone, where the LAN is on a camping and people being their tents and caravans as well as their PC's in the middle of the summer. I always wanted to go as a kid, but could never make it work with my parents. I bet there's multiple people here who are gonna comment how cool it was and possibly still is.
edit: Just checked their website and it looks like they tried to reboot it after COVID but the tickets got too expensive and they couldn't get enough people.