Surreal math humour

I've been playing around with reddit as a filter for news (triggered by Gus Mueller's brief post about dissatisfaction with slashdot and digg) and came across this fantastically weird and surreal comic by Randall Munroe.

(If someone could explain this one to me I'd be most grateful. It's been a while since I've done any chemistry)

My favourite so far is Schrödinger's Comic, but Pillar is coming a close second, and I still haven't finished going through the archives.

Well worth adding to your daily feeds.