A little searching on the Internet and I came across this tutorial on the blog web designer wall (you'll find some other great tips there as well). Here are my step-by-step instructions for creating a zig-zag line.
Start by creating a straight line with your Line Segment Tool. I have changed the color and the stroke weight to 30.
|The default zig zag settings in my program.|
|In this version I increased the size and the number of ridges to seven, creating more zigs and zags.|
|Choosing the Smooth radio button allows you to create a rounded transition between your peaks and valleys.|