Can someone explain in really simple terms the difference between Sigma and Pi bonds?

Answer 1

There is no easy way without drawing diagrams and diagrams are somethings these boards can't handle. So below are some pictures I found on the net. The long and short of it though is that sigma bonds are formed by the end to end mixing of two orbitals while the pi bonds are formed by the side to side mixing of two p orbitals.
http://dl.clackamas.edu/ch106-02/pibonds.htm