HTML5 Figure and Figure Caption Elements is an excellent tutorial with good code examples.
A couple of people are talking about the proposed ‘main’ element in HTML5 in On HTML5 and the proposed main element and The ‘main’ Element. Here’s the proposed ‘main’ element spec, by Steve Faulkner, that prompted the discussion. To contribute my opinion to the discussion of the proposed new element, I think it would be a valuable addition to HTML5. There is so much confusion as to the proper tag for the main content area of a page – should it be a div? A section? Something else? A new element with the semantic name and purpose ‘main’ is perfectly clear as to purpose and use.