From Bulbapedia, the community-driven Pokémon encyclopedia.
The Pokémon Exhibition is an annual festival held in Florando in the region of Johto. It is a gigantic outdoor Pokémon entertainment festival where Pokémon Trainers and Pokémon come from around the world to put on shows and perform. It is why Florando is famous. This festival, according to Brock and Misty, is advertised in Pokémon Trainer Monthly.
This event was featured in Flower Power.