Codecademy teaches JavaScript programming through the browser: follow instructions, type in code, move on to the next step. This is similar to the (slightly more amusing) Rails for Zombies.
Browser-based code classes look promising for classroom teachers: there’s no need to install compilers or even text editors, making this environment much easier to set up in a lab. Students can also continue their work easily at home, with (some level of) instant feedback from the built-in help system.
The associated Hacker News post has some interesting suggestions, and the comments from non-programmers about the course’s difficulty can be quite enlightening to anyone trying to teach a programming course.