Sencha Animator is a new HTML5/CSS3 small-scale animated widget production tool. Output for Apple iPad, iPhone, Google Android, Google Chrome browser. Currently offering a free Windows beta, although I’d guess it may be time-bombed or crippled in some way. Possibly a useful alternative to Reallusion’s WidgetCast Pro (which can only output Flash) if a client requests iPad /iPhone content.
Also available for free is IBM’s Maquetta HTML5 editor, although that seems more focussed on teams building out the wireframe sketch of a large website than on games and animation. That’s not to say that some bright spark might not find a way to make it do cool stuff, though.