WiiRevealed

Unlockables:

Getting pro in either tennis or boxing:
  If you get pro, which is over 1000 points, then in either sport, the reward is a bigger audience, and all of your Miis that aren’t being played get put into the audience. If you make a bunch of random Miis, they will all be there.
 
Special Bowling Ball:
  Get to pro level to unlock a bowling ball with diamond designs on it.

Secrets:

91 Pin Strike in Power Bowling Training:
  To get an automatic 91 pin strike in the last round of Power Bowling, Throw the ball on the right or left rail (depending on if you are right or left handed) so that it stays on it the whole time. If it reaches the end without falling off, you will hear a “click” and an explosion. Then all the pins will fall down from the shock wave. NOTE: This only works on the last round.

Pitch Underhand:
  While pitching, press 2 before throwing. To return to normal pitching press 1.

If you have your sensitivity on you sensor maxed out, you can replace the sensor bar entirely with a pair of candle sticks.

Wii Bowling:
 In Wii Sports if you hold the d-pad in different directions while loading a game of bowling you get a different color of bowling ball.

 Left=Pink/Red | Down=Green | Right=Gold | Up=Blue (default).

Wii Tennis:
 To change the tennis court to the blue practice court, press and hold (2) at the warning screen that shows after selecting characters. Also Hold the 1 button for the Green (default) feild.

Classic controller has analog shoulder buttons. With the GC “click” at the bottom.

You can place the sensor bar upside down and it doesn’t reverse the directions of your movements.

In Wii Sports Bowling, when you press up on the Directional Pad, it will zoom in on the lane. The zoom in sound is the exact same sound from Super Mario 64 anytime you moved the camera.

In Wii Sports Bowling, you can release on the back swing and throw the ball backwards. It scares all the Miis behind you.

When you get an e-mail, not only does the disc drive light up and pulsate blue, but your Wiimote sends out a little chirp

The plasma burin reduction kicks in the second the Wiimote shuts down.

When the message board records your play time, if you don’t exit to the Wii Menu before you power off the machine, it records the play time as “other”. If you properly exit to the menu and then shut off it will record it as the correct game.