From Bulbapedia, the community-driven Pokémon encyclopedia.
The Wobbuffet Festival is a small annual festival held in Wobbuffet Village, shown in Wobbu-Palooza. Trainers who own Wobbuffet gather to join the villagers in games, feasting and a night-time party with fireworks. The symbol of the festival is a giant model of a Wobbuffet in the center of the village.
To honor the spirit of Wobbuffet never attacking first, Pokémon battles are forbidden within the village during the festival.