Some Warehouse Keeper's medals that were being delivered to the Town of Oren were stolen by monsters. Recover them and take them to Warehouse Freightman Cliff of the Town of Oren or Warehouse Chief Baxt of Hunters Village and you'll be allowed to play bingo.
Monsters to Hunt -
Tanor Canyon: Nightmare Lords, Nightmare Keepers and Nightmare Guides.
Dragon Valley: Hunter Gargoyles, Dustwind Gargoyles, Thunder Wyrms, Dragon Bearer Chiefs, Dragon Bearer Warriors, and Dragon Bearer Archers.
Skyshadow Meadow: Connabis, Sanhidros, Cadeines, Innersens, Luminuns, and Bartal.
Sea of Spores: Rotting Golems, and Giant Monstereyes.
Outlaw Forest: Hunter Gargoyles.
Hunters Valley: Weird Drakes.
Blazing Swamp: Tulbens, Conjure Bat Lords, and Conjure Bats.
The Cemetery: Grave Guards.
Forest of Mirrors: Carinkains.