jsFiddle is a very nicely made online editor for JavaScript, HTML, and CSS. Various JavaScript frameworks are supported, and there is the possibility to save snippets and discuss them with others. Progressing.js is also available, as well as a number of tools to unleash on the code. Quite cool for experiments.
Archive 4. March 2011
Toolbox, H5 and twentytenfive are Wordpress templates that are based on HTML5. I should take a look at them and see if I can't build my own theme on one of them, instead of deriving it from the standard theme. Since I am currently a subtheme of the standard Twentyten, Twentytenfive might be the easiest - but Toolbox could also be interesting because it is a really minimal theme that I could use as a real base.
balupton/history.js provides an API for accessing HTML5 History manipulation, but it also supports older browsers and uses that ugly # notation - but only when HTML5 is not available. Could be quite interesting for a project of mine.