This event series has a great long history in Europe. It all started with "The Galactic Hacker Party" in 1989, followed by "Hacking at the End of the Universe" in 1993, "Hacking In Progress" in 1997 and later "Hackers At Large" in 2001, and "What the Hack" in 2005 - the previous one was called Hacking At Random and was held in 2009.

They are all held in The Netherlands - with four years in between each event. They usually get a three letter abbreviation (GHP, HEU, HIP, HAL, WTH, HAR).

There is a related event held in Germany, also every fourth year - but amusingly two years apart from the event in The Netherlands by the Chaos Computing Club.

If you're an North American and this seems interesting - I'd recommend that you check with "Hackers on a Plane" and see if they'll arrange a trip - like they've done previously from The States over to Europe.