Well passing a single dimensional array is useful when you have a group of checkboxes.
For an example of a multidimensional array:
I'm fiddling with making a recipe database and page interface to store recipes for my mom.
So lets look at the ingridents in a recipe:
Each ingrident will have a name, a quantity, and a unit of measure
So I can put them all in the ing array with each element being an array of the name, quant, and uom.