If you’re a WordPress user, you can start playing around with HTML 5 using one of this themes:

• Brave New World, by Karl Dawson.
• H5, by Digging into WordPress.
• WordPress Basis, by WPEngineer.
• WordPress Naked, by J. P. McGarrity.
• FreeDream, by Caroline Monmerqué.
• Starkers HTML5, by Nathan Staines
• HTML5 Reset WordPress Theme, by Monkey Do.

Do you know any other WordPress themes using HTML 5? Let me know and I’ll keep updating the list!