I **love** XKCD. I've read every strip there is, and even if I have absolutly no idea what some of them are about, as I lack some scientific culture, I find myself referencing my favorite strips quite often.

I hesitated a bit to include XKCD on here, because everyone know XKCD, and then I remembered this strip :

Alt text: Saying 'what kind of an idiot doesn't know about the Yellowstone supervolcano' is so much more boring than telling someone about the Yellowstone supervolcano for the first time.

So if you're one of the 10 000, congrats, you're in for a lot of fun!

Oh, and bonus : every XKCD strip is explained in details on the aptly named explainxkcd.com

XKCD