To move 1000 bricks away by hands, it's 简单, because all you need to do is pick up bricks with your hands and throw them away, everyone knows how to do it. But it's NOT 容易 to do, because it takes time and effort.

容易Easy - means the thing isn't difficult to do. 简单 Simple - means the thing is not complex. But sometimes the simple things it is not easy to do for some people.

1. When both of them are adj. 容易: easy to do 简单: simple, uncomplicated Example: * 学中文很容易; * 中文很简单. 2. 容易 adv.: do something easily Example: * 这本书容易(adv.)看. * 这本书很简单(adj.) 3. 简单 n. briefness, simple. example: 她的风格是简单. her style is briefness.

Jing Yao's explaination is very good. Another big difference is as Alice said, 容易 can be adv, espically when u what using it directly in front of a veb. Example:1. 这个蛋糕很容易做。（You definitely can't use 简单 instead. So, it's worng to say 这个蛋糕很简单做。）2 . 这书很容易懂。3.材料很容易买到。etc......

容易 = easy 简单 = simple