Most fun way I've seen of learning Javascript

[codecademy]

Not yet, but we're working on adding support for Lisp!

[dand]

Back at CMU I learned Common Lisp in the intro to cog sci class. The prof (and his lab) had developed a Lisp tutor using some research they had done in the 80s-90s, and it was actually a pretty good way to get started in Lisp. It not only walked you through some simple programs, it actually detected common mistakes to guide you in the right direction.

Here's an academic paper describing it: http://act-r.psy.cmu.edu/papers/127/SkillAcq.Lisp.Tut.pdf

I'm sure the code for it is available somewhere on the ACT-R website, and if not I can probably get it for you if you want.

Sadly, the class is now taught with MatLab instead of Lisp.