Metastream - Watch streaming media with friends
StreamParty - StreamParty is a watch communiry, that allows you to watch video streams in sync with the people you care about, on multiple services.
Watch2Gether - Watch2Gether is an app that allows multiple people to watch the same content simultaneously and interact with each other while watching.
Hyperbeam - A better way to watch together online
Scener - A virtual movie theater to watch content with your friends
Kosmi - Digital Hangouts Reinvented