Feel like something's missing from your YouTube viewing experience -- like some good 'ol multiple-choice questions? The chronic learners among us will be happy to hear that the site is testing an interactive -- and potentially educational -- feature that lets users add quizzes to their clips. A new page on the YouTube site describes a "Video Questions Editor Beta," which lets channel owners display multiple-choice questions on top of their videos as they play. The page is pretty blank at the moment, but the beta is up and running for those who opt in. Don't get too excited, though: YouTube's disclaimer