? Space

From the Super Mario Wiki

The ? Space (also known as the Happening Space) is a green space on the Mario Party game boards. It usually activates special board-specific events that can change the outcome of a turn or even a whole game. However, in Mario Party 8, the shape was different with each board, including the tutorial. Also, in Mario Party 8, ? Spaces were not called "? Spaces" but Green Spaces instead. In some games, the player who landed on the ? space the most got a bonus star at the end of the game.

Mario Party 1 and 2	Mario Party 3	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 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 Reverse Space Single-player Space Star Space Warp Space