I was sure I had a post on this blog about xkcd, subtitled by artist/writer Randall Munroe as "A webcomic of romance, sarcasm, math, and language". It's my favorite comic; it's consistently funny, sometimes surprising, and often challenging (I've had to go do research after reading this comic more than any other comic or book I've ever read). And I've had a link over there on the right for years. But I apparently never did a post about it, or, if I did, I can't find it now.
In any case, you should be reading xkcd every Monday, Wednesday, and Friday. Don't worry if you don;t always get it: it doesn't matter, and the more you read it, the more of it you will get (and, probably, the smarter you'll be).
I thought of this because I found a conversation with Randall Munroe on the Atlantic Magazine website. After I read the article, I was even more impressed with Munroe.