Hackasaurus makes it easy to mash up and change any web page like magic. You can also create your own webpages to share with your friends, all within your browser. (via the site)
I love this amazing product by Mozilla aimed at helping educators teach students to code using HTML, Java, and more web languages by remixing current websites online. Through “Goggles”, young coders can learn programming by exploring codes for their favorite websites. Then, they can change/add code to make the site their own. The best part is the ability to send remixed pages to others. Educational resources are also included on the “Teach Webmaking" page.