? Space

From the Super Mario Wiki

? Space
Purpose	Triggers a board-related event.
First Appearance	Mario Party

The ? Space is a green space typically found on the various game boards in the Mario Party. Ordinarily they activate special board-specific events that can change the outcome of a turn or even a whole game. In Mario Party 8, the shape of the space differs depending on the board, including the tutorial map. In-game, these spaces were known as Happening Spaces up until Mario Party 6, when their name was changed to Green Spaces. In most games, a Bonus Star is awarded to the player that lands on more of these spaces than any other player at the end of the game.

In Mario Party 3's Duel Mode board, it's known as the Happening space too, and a roulette starts with three random events.

[edit] Gallery

Mario Party	Mario Party 2	Mario Party 3	Mario Party 3 (Duel Board)
Mario Party 4	Mario Party 5	Mario Party 6	Mario Party 7
Mario Party 8 (tutorial)	Mario Party DS

Spaces and Areas from the Mario Party series 1-Vs-3 Space 2-Vs-2 Space 4-Player Space ? Space Back Space Bank Space Basic Space Battle Space Blue Space Bowser Space Candy Area Capsule Space Challenge Space Character Space Coin Block Area DK Space Dice Space Duel Space Friend Space Game Guy Space Hex Area Item Space Koopa Kid Space Lucky Space Mic Space Mini-Game Space Miracle Space Mushroom Space Orb Space Power-up Space Rare Mini-Game Space Red Space Star Space Warp Space