A 'Goon Cave' is a room or space where someone spends long periods of time relaxing or watching entertainment, often with a focus on visual content. It's typically set up with a TV or monitor for easy viewing.
He turned his basement into a goon cave for weekend movie marathons.
The kids claim the living room is a goon cave now, no one can play there.
She built her own goon cave with a big screen and comfortable couch.