I purchased the Embers video for Assassin's Creed: Revelations on XBox Live, but I can't find where to view it. Where do I go to see it? I've tried in all the menu options in AC:R and I looked in the XBox Live Dashboard, but no joy.
Purchased or downloaded videos will typically show up and be played in Zune.
From the dashboard, go to Video Marketplace, select Zune (should be first). Under there should be an area for Video Library that contains anything downloaded or purchased.