Using Category Dates
From your Dashboard menu go to Categories.
If a category is only relevant on a particular date or date range then you can stipulate this within the 'Advanced' panel when adding/editing a category.
Examples may be Halloween products, Christmas products, Valentine's Sale or an End of Season Sale.
Simply enter the date you wish the category to be visible and the end date (after which the category will be hidden). Note that the category will appear at 00:00 UTC and disappear at 23:59 UTC on the dates selected.
Category Display Options
In some instances you may wish to show only the sub-categories for a menu option. For example, if your Main Category is "Computers" with child categories of Desktop, Laptop and Apple Products underneath; you may not wish to show all 'Computers' under the initial header.
In order to enable this:
Navigate to Categories
Edit the relevant Category
In the Basics section, you will see Category List/Index View
Tick the Display Sub-categories Box
Head to the Shop Front and check it works
You will need to add Category Images for each of the 'Child' categories under the one selected above. This will make it easier for customers to select the relevant category and find what they're looking for.