Is there anyway to give a category level discount? I want to run a special for all items that are in only one category.

When you set up your discount code, you will have a pull down list that will allow you what category/sub-category you want the discount to apply to.

If you have more than one sub-category that you want the discount to apply to. Simply create another discount line, with the same discount code and select the other sub-category. You will need to do this for each sub-category you want discount to apply to!

Hope this helps!