Goebie volleyball is an Easter egg minigame that can be activated after the beastmaster fight. The four gongs that hang from the walls should be restored and rung in the following order: North, North, South, South, West, East, West, East. If done correctly, the minigame will begin. The game is curated by Lefty and Righty.
Goebie volleyball wasn't found by the players for a number of months after its release. It was revealed at RuneFest 2015.