An anonymous reader writes "Similarly to Google with Chrome Experiments and Microsoft with Internet Explorer Test Drive, Mozilla has developed an HTML5 demo site to showcase the latest features supported by Firefox 4. Mozilla's Paul Roget writes, 'Firefox 4 is almost here, and comes with a huge list of awesome features for web developers. In order to illustrate all these new technical features, we put together several Web demos. You'll see a couple of demos released every week until the final version of Firefox 4. You can see the first 3 demos online now on our brand new demo web site: Web O' Wonder. Unlike certain other HTML5 demo sites, Mozilla's site works in any browser that supports the features used in the demo."