Pinball
Open up pinball and after it's loaded type in the words, "hidden test" it may appear to be normal at first but simply click anywhere with your mouse and the ball will follow (you can control the ball with your mouse).
If you press the letter "h" you can type in your name for a high score of 1,000,000 points.
You can also press the letter "r" and it will increase your rank.
Solitare
Open up solitare and press, "Shift+Alt+2" and you will automatically win.
Press, "Ctrl+Alt+Shift" while you're in 3 card draw mode and it will draw them one at a time.
Freecell
Open up freecell and while playing press, "Ctrl+Shift+F10" and you will be offered to press Abort, Retry, or Ignore, press abort and move any card then you'll automatically win.
Go to the game menu and pick "Select game" you will be prompted to type in a number from 1-32000, type in either -1 or -2 and they will be arranged in order.
Minesweeper
Hold your mouse inside the game window and type the letters, "xyzzy" then hold "shift" and there will be a small white pixel in your top left corner of the screen and it will turn black whenever your mouse is on a mine.
Alternatively, type "xyzzy" then press "Shift+Enter" then press "Enter" again and the small pixel will change without you having to hold shift.
I have heard this one from friends but i haven't gotten it to work, they say to hold down the right and left mouse button so a 3x3 imprint comes up then to press the "Esc" key while doing that and the timer should stop, hasn't worked for me but someone reply and let me know if you have gotten it to work.