In the organizer's words:

Cassiopeia Wintergarten: Loud, tasty & free! No Silent Night music, just mulled wine, beer, great music, the best food & curling.
When the city is drowning in glitter and the scent of cinnamon stars and contemplation clogs everything up, we light the fire barrels: The alternative winter garden in the Cassiopeia Sommergarten on the RAW grounds is getting underway!
Instead of tinsel, there'll be pizza slices from Slices of Doom, mulled wine with a kick and cold beer that goes down better than any "Ho Ho Ho".
So wrap up warm and come to our winter garden, where snowflakes melt on beer and nobody plays Last Christmas (except maybe the metal version).