Norwegian User Oracle's Group conference #ougn17 took place on the ferry with 8 parallel sessions.
What is interesting this was 10 year anniversary for Oracle user group on a ship and by moving to Germany(Kiel) we were able to learn something new and relatively visited 4 countries (Norway, Germany, Sweden and Denmark).
Here is a good example while listening sessions I got a chance to see 16km long bridge between Sweden and Denmark.

Conference halls on the ferry are big and exceeded expectations, despite on that fact that screen was swinging all the time. Internet was all trip long through the satellite.
During the conference lunch we were able to visit the sponsor's stands and all sorts of activities.

And of course I got new knowledge to share with my colleagues about new technologies and trends and got some gift from sponsors for my colleagues!
