How do I print a specific category from an Outlook calendar?

You can print only what you see in Outlook folders. If you want to print only a specific category, for example, or only items that aren't marked private, you need to filter out the items you don't want to print. You can create a filter on the currently open view with the View, Current View, Customize Current View, Filter command.

If you plan to print that view often, create a new named view that you can switch to anytime. You can use View, Current View, Define Views to create a new view from scratch. Or if you're already displaying a filtered view, in the current view drop-down list on the Advanced toolbar, type the name of the new view you want to create, then click Enter. This action creates a new view with the name you entered, and the view uses the current view settings for that folder.