Spent a bit of time working on a d3js version. It's super ugly because I just hacked it together while learning how d3js works; I'm sure someone will come along and do it much better ;)

http://bl.ocks.org/3815828

Nice updates! Riffing some on what you put up, I forked and added the font and a white background line to make a gap when the lines overlap

http://bl.ocks.org/3818779

Looks good, I like how you added the style to the axis, nice touch. I did something similar but without the axis

I imagine it's only a matter of time before Mr Bostock catches on to this and creates an example: http://bl.ocks.org/mbostock.

d3.js should probably have you covered.

d3.geo has most of these projections now, as a start: http://xkcd.com/977/

http://bl.ocks.org/3764187 http://bl.ocks.org/3739752

Haha, maybe if I have time! It might make a fun custom line interpolator, one of the features added in 2.10: http://bl.ocks.org/3310323

Can somebody squiggle the fonts too??

Such lib is not hard to write. Somewhat limiting but simple version could just be a Canvas API wrapper that breaks down lines and curves into smaller lines then jiggle the points randomly before rendering the points out using Catmull-Rom to Bezier spline conversion.

Complicated part is in intelligent fragmentation and jiggling based on hand velocity and hand muscle modeling but it's pretty easy to get decent result. Another technique to combine this with is drawing each path more than once but, like bold fonts, result is not as generally useful.

I wrote up a quick example using d3, adding some jitter to the graph line gives it the hand-drawn look, plus used a font from the xkcd forums

http://bl.ocks.org/3816112

Not a library, and not for graphing, but somewhat inspirational: http://hakim.se/experiments/html5/sketch/