Very simple color picker for OS X 10.10 Yosemite.
Since "choose color" in AppleScript doesn't work perfectly on Yosemite, this is a simple alternative.
You can download the binary file from https://github.com/hirakujira/ColorPicker/releases/
There are some plugins for color picker:
Skala Color http://bjango.com/mac/skalacolor/
Hex Color Picker http://wafflesoftware.net/hexpicker/
MIT. Please kindly keep the credit of contributors.