Mario Party 6 stars Mario and crew as they party from dusk til dawn and back again. It plays much like the previous entries except the plot for this is that the sun and moon (Brighton and Twila) are fighting causing the time of day to go all out of whack. To stop this, Mario and crew decide to have a Mario Party with both of them as hosts. The main gimmick of this one is that every 3 turns the board changes from night to day. In addition, there are also new mic minigames, using the mic that it comes with.
The game plays much like the other Mario Parties especially the ones on the gamecube. You still roll a 1-10 dice and the goal is to collect the most stars. You also obtain orbs to mess with your opponents. At the end of every turn, there is a minigame netting the winner some coins. However, the time of day changing aspect changes the game up alot. First of all, the Bowser and DK spaces are on the same spot but switch on night and day, respectively. In addition, the board changes every cycle of day and night. For example, in Professor E Gadd's lab, the orb swapping machine turns into a machine that turns orbs into coins and the center walkways rotate, changing the path. The time of day change also influences a number of the minigames often changing the aesthetics and sometimes the idea of the game.
The mic minigames have some interesting aspects. Most are either 1 vs 3 where the one using the mic against the other 3 or its a free-for-all using the mic in a rotation. The commands for the mic can be accessed via the R button in those games if you do not have a mic active.