Some pictures regarding the Texas Advanced Computing Center (one I am currently interested in) here: http://www.tacc.utexas.edu/resources/hpc/
If you see the two supercomputers they have, Lonestar and Ranger, they are not like the normal computers you and I would see every day. Nor do they even resemble anything like it despite the difference in scale.
I was just wondering why these "supercomputers" look the way they do (giant rectangular boxes packed together across a room). In any case, each rectangular box looks like its own individual unit, so wouldn't a "supercomputer" pictured here actually be multiple computers (or whatever these boxes are) working in tandem, rather than one giant "computer"?
*edit: possibly a better visual depiction of the 'boxes' and their properties I am referring to: http://www.youtube.com/watch?v=gmGlrpjsauM