Have a look at craftyjs.com - not very mature, but moving fast, and really nice to work with.
I would suggest to take a good look at LimeJS.
Not to be a downer (I'm sure there was still a lot of work in it), but when it loaded I thought "oh, it's just Biolab disaster" (the first demo game of impactjs: http://playbiolab.com/). I think this game is just a "reskin".