The W3C's new HTML5 logo is here! Visit http://www.w3.org/html/logo for free downloads of image files, free stickers, and other fun stuff.
Although some may question the need for a "logo", it's one way to spread the word about this emerging technology.
The key is the concept of progressive enhancement — use HTML5 new elements, attributes, and features to enhance web pages rather than for mission critical requirements. My new book, Web Design Basics: HTML5 & CSS3, takes this approach.