The Vibrance adjustment allows you to gently change the color saturation of an image. It's useful when you need to increase the intensity of muted colors in a photo and leave the already well-saturated colors.

Select Image -> Adjustment -> Vibrance... to display the adjustment parameters in the Settings Panel.

You can also use the Vibrance adjustment layer (Layers -> New -> Adjustment Layer -> Vibrance...) which will affect all the underlying layers without changing their content.