From Bulbapedia, the community-driven Pokémon encyclopedia.
Poké Floats is a stage in Super Smash Bros. Melee that is set in the sky over Kanto. In this stage, the characters battle on top of huge Pokémon-shaped balloon floats. It was one of the two stages to succeed the original's Saffron City, the other being Pokémon Stadium. The players battle on slowly-moving Pokémon balloons and must jump from balloon to balloon in order to survive. After a set amount of time, the characters will start over again at the Squirtle balloon.
List of Poké Floats