For Golf, by holding down 2 when picking courses, you can disable the Golf Map, Wind info, Hole/Par info, and the Swing Meter for a more challenging game of golf.
For Baseball, pressing 2 once will switch the way the pitcher throws to an Underhand/Sidearm pitch, and pressing 1 once will restore it to the default Overhand pitch.
For Bowling, holding down the Left, Right, or Down directions on the D-Pad during the black screen before starting a match will change the color of the bowling ball to Red, Gold, or Green respectively. Holding Up makes the color of the bowling ball Blue, although this is also the default bowling ball color that is used for Player One without holding down the D-Pad at all.
The game's internal name is "Sports Pack For Revolution", which refers to the Wii's pre-release codename, "Revolution".
At one point in development, Wii Sports was being developed to feature Mario characters rather than Miis.
For Tennis, by holding the 2 button at the black screen before the screen where you decide where your players will be, the court will be the blue training court.
In "Bowling", if the player's ball enters an alley that isn't their own, the crowd will laugh at them.
It is possible in "Bowling" to throw the bowling ball into the crowd, accompanied by a surprised reaction from the crowd (who scream and jump to avoid the ball) and an automatic do-over that does not affect the player's score. To throw the ball into the crowd, simply let go of the B Button during the back swing, and it will fly out of your Mii's hand and into the crowd.
Wii Sports has sold 81 million copies world wide. This outsells the entire Legend of Zelda series (70 million global sales across all games). This is due to the game being bundled with the Wii console.
In the training mode in the Bowling game, when you get to the last level in which you have to hit 91 pins, throwing the bowling ball in just the right position on top of the gutter will get you an automatic strike, accompanied by an explosion sound.