multiple organizations have. anyone who bought a ps3 at the release may remember an app called "folding home" which was an effort to make the worlds largest and most powerful networked supercomputer, which was able to perform at a computational peak in the petaflops (most supercomputers operate in teraflops)
additionally, the initial cost of building a ps3 networked supercomputer was more expensive, being around $9k or so, but paid off as each computation that was intended to be made on said supercomputer cost around $6k in computing time at other supercomputing facilities.
http://en.wikipedia.org/wiki/Cell_(microprocessor)#Supercomputing
the ps3 is and was more than just a gaming system, it was the commercialization of some pretty groundbreaking technology.