I've always kept half an eye on the progress of the long, long, LONG awaited Perl 6, and more specifically on its cross-platform, dynamically typed VM at its base, Parrot.

One of the more exciting features of Parrot is its advanced language parsing features which make implementing a new grammar almost trivial -- the Parrot Grammar Engine (PGE). A humorous, but practical example of using PGE can be found in this LOLCODE implementation.

That, tied with this post from Patrick Logan makes me think that a JS-like language implemented in Parrot could be a very, very useful exercise.

More to come...?