WarioWare, Inc. (stage)
From the Super Mario Wiki
WarioWare, Inc. is a stage based on the WarioWare series in the game Super Smash Bros. Brawl. Normally, the stage looks like a reverse-colored child's drawing of the inside of an elevator, much like in the original WarioWare games. Occasionally, the elevator in the background will open up, and the players will then go through a microgame setting, and have to try and survive the different conditions. The players will be rewarded everytime they complete a microgame, either getting healed, growing big (like if a player got a Super Mushroom), or get invincible (like if a player got a Starman). A Wario Bomb is shown on the side, which acts as a timer. The fuse will be lit at the beginning of the microgame, and when the Bomb explodes, the players return to the main area of the stage. Sometimes, the players will be thrown into another microgame almost immediately after (as evidenced by the main platform not coming back when the players return), resulting in up to three consecutive microgames. It continues on like this, until the fight is won.
This is the list of games that appear throughout the stage.
 Starting Songs in My Music
 Unlockable Songs in My Music