The great thing about the Arduino is that the interfacing is much simpler than the Raspberry Pi. By connecting a breadboard and a few components there is so much you can do via the 'pins' which are so simple to control in code.
AS a perfect example of this, here is an excellent and simple tutorial from Joe Coburn of www.makeuseof.com on creating a set of simple controllable traffic lights.
I particularly like this as its a perfect starting block for you to advance your logic skills by adding further lights and buttons and creating relationships between them.
Have fun, cos if it ain't fun, it's not worth doing!
