Good Things Come to Those Who WHITE
A pint of the black stuff becomes a pint of the white stuff with the launch of a creamier new version: "Guinness White".
Guinness is made from the same raw ingredients as regular Guinness Draught - hops, barley, water and yeast, but the barley is frozen instead of roasted, which provides the white colour.

I have to admit, this April Fools made me shriek in horror/delight (not even sure actually, I know I'd try it!) so they had me for a nano-second there, scaring the Guinness-purist in me and delighting my try-anything-new side.
Very cute. Announced at facebook, which I'm so not going to link to because, pshaw, pfft, facebook, how lame.
The joke however, fun-niiii.