Skip Ad is a Google Chrome extension that will close ads automatically when playing a video on YouTube. You don't need to wait for an ad to play and close it manually; instead, the extension will find the current video you're watching and automatically close it for you.

To use it, simply add the Skip Ad extension on your Chrome browser and click the X button in the upper right corner of the ads that pop up during video playback. And it works with almost every video format, including HTML5 and Flash video, as long as the page is loaded through YouTube.