And if yesterday's SLI supercomputer didn't impress you, what about this Helmer - an affordable 6 Quad-Core computer cluster?
With 6 quad-core computers and a total of 48GB RAM, it was assembled to help render 3D animations.
What's original about it is that is relied on a IKEA file cabinet as casing/chassis - which help shave a few hundred (thousands?) of dollars.
Check Helmer's official page to learn all you need to know about this awesome project.