He willingly allows noncommercial republication of his work, asking only that there be a link back to his website. He's Randall Munroe, and his brilliant webcomic, xkcd, can be found here: xkcd.com.

The "Zombie Marie Curie" strip is an older one and I don't have an exact link to it.

The very earliest strips are generally less interesting. Even so, if you were to start at http://xkcd.com/1/ and read them all, you couldn't go wrong (other than the impact on your productivity).

Don't forget to hover your cursor over each cartoon to see the additional mouseover text.

Meh.

I, myself, first read xkcd when I followed a link from a DU post. I'd never heard of it before. Perhaps that history is why I'm always keen to see the link included.

Odds are that your thread will reach at least one person who didn't previously know about xkcd.