Ask Slashdot: Passively Cooled Hardware For Game Emulation?

akutz writes "I recently sold a 2011 Mac mini on Craigslist because after using it to rip my Blu-ray collection, I tried to use it as an emulation station connected to my TV. However, emulators like Dolphin, BSNES, etc. would cause the Mac mini's fans to spin up like turbine engines — much too loud for my liking. I ask, therefore: What hardware would you recommend for building a passively cooled mini-system that will serve as a media center's emulation station?"