Today's Obsession: Maqetta
If you’re having a little trouble getting some of the newer HTML/CSS3 properties to come to mind, here’s a cool tool that makes them for you. Then you can rip apart the code and copy/paste until it sticks. Don’t laugh; I don’t know a single coder who doesn’t learn this way.
Maqetta’s a new, open source, and freely-adaptable tool which you can save to your own server and run locally, so you’ll never have to worry about another valuable resource shutting down on you (looking at you, Del.icio.us). Basically, it’s a visual editor for HTML/CSS3. It supports a lot of juicy features like coding of interactive states in a visual editor, support for libraries, widgets and themes (such as jQuery, color pickers, and CSS rules matching those, respectively). You can sign up for an account at their site, and take it for a test drive first.