There will be a big get-together to celebrate a decade of WordPress. The meetups seem to be arranged on a subsite of meetup. You can RSVP here and/or on this url http://www.meetup.com/WordPress/Copenhagen/
Details of the event...
1. Find a cool place that people can meet up and hang out to celebrate. To keep it easy and light, having people pay for their own food and drinks is 100% okay.
2. Promote your party to local tech groups, meetup groups, bloggers, and press.
3. If you get above 50 people attending, we'll try to send you some WordPress stickers and buttons.
4. On May 27, make sure everyone has a good time, meet some new WordPress friends, and share your photos and videos for our 24-hour worldwide 10th anniversary party photostream. We'll send you details on how to upload to the central blog.
All WP10 parties should be free to get in (no cover charge).