Firefox only (Windows/Mac/Linux): The YouTube Cinema Firefox extension lowers the lights on any playing YouTube video, removing distracting ads and comments so you can focus on the video. The popular video sharing site added theatre view for select videos a few months ago, but the feature still isn't available for most videos. With YouTube Cinema installed, clicking on a new video opens that video in a custom tab where you can adjust the video size, background colour, and view the title and description. The extension works well and is fairly configurable, but it's a little overreaching. For example, it'd be much better if it just mimicked the default Lights Out feature rather than hijacking the expected YouTube experience altogether. Still, if you prefer a video-only view when you're watching videos on YouTube, YouTube Cinema does the trick. YouTube Cinema is a free download, works wherever Firefox does. Alternately, you may want to check out the YouTube Theater feature included in our very own Better YouTube extension.