Hack.lu
hack.lu (also written as HACKLU) is a yearly computer security conference held in Luxembourg. The first conference was organized in 2005 and held its 9th edition in 2013.
At hack.lu attendees share the implication of new security discoveries with a focus on any information systems that can be potentially "hacked". In the scope of European Information Security conferences hack.lu is one of the oldest conferences running.
CTF
Since the first conference a capture the flag event has been organized. In recent years FluxFingers from Ruhr-University Bochum (Germany) are the event organizers. (4th time in 2013) The event usually lasts 48h with the possibility to participate remotely. But only teams who have 1 person physically present will be able to claim their prize.