((Since I keep advertising it but seem not to have remembered to describe it... >_>))

Codecademy is a site that offers free courses in various kinds of code, including HTML (and thus CSS), Javascript, Python, and Ruby. No, it doesn't bombard you with ads or malware - as far as I can tell, it's a genuine power-of-the-people effort.

The interface is easy and enjoyable. It introduces you to a concept, has you do a simple exercise, and then goes onto the next concept. The only problem so far is that the HTML course occasionally glitches up and doesn't respond to the Submit button properly, but it's not grading you, so you don't have to worry about that affecting anything. And yes, you can go back and review a previous exercise at any time - it's pretty well laid-out, so you'll be able to find your way back.

It also has a little scoring system so you know how many exercises you've done today and how many days you've been going at Codecademy without interruption. So, if you're feeling competitive, you can work on racking up as many points as you can in any given day. :P Wonderful procrastination tool...

Apparently I've been on there for twelve days and done very little in that time.

Why do I recommend it for the casual LJer/Dreamwidther? Because it will enable you to actually read CSS stylesheets without it all looking like Greek (er, or... Chinese or something, in aikaterini 's case >_>), it will allow you to program up short little things for your own entertainment and use, and because it's a browser-game-like site that will actually increase your knowledge and be useful in the future. I mean, with all due respect to Dragon Cave, GPXPlus, and the like, mass-clicking doesn't benefit you in the long run. Learning programming languages will - even if it's as a side hobby and the most you do with it is create custom journal layouts and run amusing little text programs.

So please do check it out, if you have a minute. I promise that you won't regret it.