I want to learn web apps. What language should I learn and how?

I'm a business student who has interacted a lot with devs and hackers over the last few years and am sick of not having the skillset to get stuff done myself. What should I learn, and what do you think is a good way to go about learning and practicing so that I can begin building web applications/sites?<p>From what I've read, the following are highly recommended: Django Ruby on Rails Javascript<p>I have some experience with python, css, and html - but none of it is what you would call 'practical' [hasn't been applied to any real projects].<p>Thanks for any advice you can provide :)