If you love robotics this project is for you! Lifehacker have put together a fantastic set of instructions detailing how and why you should build your own robotic arm. Not only is building your own robotic arm super cool, but it is also fairly comprehensive in teaching you about lots of Arduino basics. Indeed, once you have built your robotic arm you will have learnt about controlling servos, bread boarding, Arduino coding and more.
Depending on your interests you can modify your robotic arm so that you can control it using an IR remote control, over the internet or even using your Nintendo Wii remote! If building your own robotic arm sounds like something you would like to do check out the following link.