ARGs

ARGs or Alternate Reality Games, are generally websites that utilize the real world to tell a story that may/may not be altered by the player's actions. Many ARGs involve intense player interaction, usually involving multimedia like telephones, email or actual players. Many ARGs have been spawned on the internet, and there are bound to be plenty to fill your request on YouTube.

There are many creepy ARGs on the web and usually a thread about some on /x/.

List of Spooky ARGs:

MarbleHornets - https://www.youtube.com/user/MarbleHornets/videos

SCP Foundation - http://www.scp-wiki.net/

Dionaea House - http://www.dionaea-house.com/

b74287346ef38c3e - www.b74287346ef38c3e.link

List of ARGs for Advertising/Media

Halo 2: I love bees