Adam DeConinck, high performance computing (HPC) systems engineer for NVIDIA, built a personal computer cluster in his spare time. While not exactly high performance, especially when compared to the systems he maintains for Amazon and his employer, its case is made of Lego and seems to be under a third of a cubic foot in volume.
Image source: NVIDIA Blogs
Raspberry Pi is based on a single-core ARM CPU bundled on an SoC with a 24 GFLOP GPU and 256 or 512 MB of memory. While this misses the cutesy point of the story, I am skeptical of the expected 16W power rating. Five Raspberry Pis, with Ethernet, draw a combined maximum of 17.5W, alone, and even that neglects the draw of the networking switch. My, personal, 8-port unmanaged switch is rated to draw 12W which, when added to 17.5W, is not 16W and thus something is being neglected or averaged. Then again, his device, power is his concern.
Despite constant development and maintenance of interconnected computers, professionally, Adam's will for related hobbies has not been displaced. Even after the initial build, he already plans to graft the Hadoop framework and really reign in the five ARM cores for something useful…
… but, let's be honest, probably not too useful.