Grove Starter Kit for Arduino
Grove is a modular electronic platform for quick prototyping. Every module has one function, such as touch sensing, creating audio effect and so on. Just plug the modules you need to the base shield, then you are ready to test your ideas.
You also get a guide book with basic projects to get you started and help you to understand how to create more complicated projected with your Arduino.
More information is available on the website of Seeed Studio.