From Randall Munroe:
In a recent email exchange, Mike Monroe (Secretary & Treasurer of PICMG) pointed me to xkcd, a blog of wonderful cartoons on "romance, sarcasm, math, and language," that his physicist son has been publishing for some time now. xkcd is famous enough to have it's own Wikipedia entry, so you may already have seen these.
I love the topics he covers. As the disclaimer puts it
Warning: 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).