Color Palette  

This shows you the current foreground and background color.

-While the sliders that you can either navigate through or by entering the RGB, CMYK ect, colors numbers.

This works as the color picker box, while hovering over this slide, an eyedropper appears where you can just click on the desired color. There is also a small box on the right that has the default colors of white and black, that you can always pick.

Through this icon on the top right of the color palette you can access the menu below.

This menu gives you many options that you can choose from:
Grayscale Sliders: this changes the mode of the color palette to be a gradient of gray.
RGB sliders: This would change the color palette to contain only colors for the screen
CMYK sliders : This would change the color palette to contain only printing colors.
Lab Sliders : This would change the colors to a human vision based colors
Web Color Sliders: This would change the colors to a web based colored.