Check out this Stealth activities demo - Coming soon in Moodle #Moodledev - Moodle World | moodle3 | Scoop.it
From www.moodleworld.com - March 25, 2016 10:28 AM
Stealth activities which were requested in Moodle tracker a long time back since 2006 are coming soon in Moodle and currently under peer review process. A prototype to test out the functionality of stealth activities is setup at Moodle Prototype site here.

Stealth activities are those activities which are accessible to students, but not listed on the course front page. The course creator will manually put a link to the activity somewhere else in the course and the activities would be available by following URL but hidden from the course page.

Via Miloš Bajčetić