If you would like to create an event that is not linked in your site (does not show up on your calnedar or events list) please follow the instructions below!
1) Add a new event through the Events Module
2) Save your new event
(An event cannot be marked private until it first exists in the website)
3) Once your new event has been saved, go back in and edit the event
4) Scroll down until you see a link for "Show Advanced Permissions"
5) In the advanced permissions find the check box for "Enable Private URL"
The listed URL can be distributed to those that you would like to have access to the registration page.