Lego and Raspberry Pi have come together again. First there was the University of Southampton and now this fantastic project by the University of Glasgow's School of Computing Science. Using 56 Raspberry Pi boards, their team have managed to create an affordable, working cloud computing infrastructure which is available to researchers and students of the faculty.
They have documented their adventures on a blog which contains images of the various incarnations of their project through to the current stage. http://raspberrypicloud.wordpress.com/blog/