ShareTube - Watch YouTube, synced with friends.
Netflix Party - Netflix Party is an extension for watching Netflix remotely with friends and family for movies nights with that long-distance special someone.
&chill - Watch YouTube & Twitch videos with people online
Hyperbeam - A better way to watch together online
Picaboo - Picaboo is a web-based image publishing and printing service that allows you to create personalized photo books, cards, and scrapbooks.
Metastream - Watch streaming media with friends