In the page's words:

The hotel666 was founded in 2004 to give the metal scene in Lower Saxony a voice. Initially limited to Braunschweig, the association is continuously expanding and, together with its partners, offers everything a metal fan could wish for, from underground concerts to parties and festivals.
The non-profit association cooperates with countless organizations, locations and clubs. (Lebenshilfe BS, B58, KufA e.V. etc.)