Take a picture on the web, any picture will do as long as its accessible by a URL, and attach a comment to all or parts of the picture which is displayed in a cartoon bubble. The bubble can also be set to pop-up on mouseover or mouseclick.
Start with a large picture or a series of related pictures placed on a wiki page in a row, a column, or a grid. Allow people to change or comment on all or parts of the pictures using tools on the web page. Put four in a row and let people create a toon by filling in the bubbles.
Fill top half of a page with a large image. That's the stage. Fill the bottom half with images of characters and props. Let people play with the characters and props and share the experience with other players and spectators. Record positions in time and let people replay one scene at a time. For kids and adults only.