Here is a 1-paragraph summary of the text: The article discusses hacking the Twilio Client SDK to play videos over the phone using WebRTC. It starts by adding a media element, such as an HTML5 video tag, to the page and creating a global JavaScript variable that captures the audio stream from the video element. The article then modifies the Twilio Client JavaScript SDK to inject the audio stream into the phone call, allowing for dynamic audio playback over the phone. This hack can be used for various purposes, including mash-ups, virtual instruments, and testing audio via PSTN, and is demonstrated with a working demo that can be viewed on YouTube or GitHub.