The first (and obvs. best) Meet Magento event in the world, kickstarted by Guido Jansen in 2009 and annually organized in our tiny orange country. The 2017 Edition will be in DeFabrique in Utrecht on May 1oth.
In The Netherlands we have 12 meetup groups (one for each province). It started in 2013 in Amsterdam and we have now organized over 60 meetups accross the country covering many topics like SEO, E-mail marketing, Extensions, Payment providers, New Relic, MageFlow, Hosting etc. etc.