This is our top-level category, or looking at it another way, it is the root category.
Check out Category:Video game sales for all the good stuff!
The "Vgsales" category is intended for all articles about the subject matter of the wiki, whilst "Organisation" is intended for all administrative matters. A full list of existing categories can be found at Special:Categories.
To add a new category to a page, just add
[[Category:Categoryname]] to the end of the article or existing category page.