Virtual Mouse Brain is Penguin-Powered
One of GNU/Linux's unique properties is its ability to run on dozens of platforms (whereas Windows runs on precisely one, that of Intel's processors). GNU/Linux can power anything from an embedded processor in a tiny industrial device, through mobile phones, PCs, minicomputers, mainframes right up to massively-parallel supercomputers.
One of these, IBM's Blue Gene/L, has recently been used to model part of a mouse brain in near-real-time. Which means that GNU/Linux has just added a platform, albeit as an emulation. (Via Jamais Cascio.)