As the site states, "This comic occasionally contains strong language (which may be unsuitable for children), unusual humor (which may be unsuitable for adults), and advanced mathematics (which may be unsuitable for liberal-arts majors)."
Needless to say, this liberal arts major really enjoys it anyway. Xkcd deftly intertwines mathematics, science and technology with humor, social awkwardness and dating, often with very amusing results. I recently took the time to start at comic #1 and click next through today, gaining the benefits of reading a full comic book online. Even after several dozen, I still found myself laughing time and again. While Randall doesn't slave away a the art side of his stick figures, the word play and scenarios are hilarious.
I hope you enjoy his work as I have. Check them out at www.xkcd.com.