At UCLA's Plasma Physics Group, to achieve accessible computational power for our research goals, we developed the tools to build numerically-intensive parallel computing clusters on the Macintosh platform. Our technology maximizes productivity because it is designed to allow the user, without expertise in the operating system, to most efficiently develop and run parallel code, enabling the most effective advancement of scientific research. Collaborating with USC and NASA?s JPL, our team has demonstrated the performance and scalability potential of Mac clusters by achieving over 217 Gigaflops on 33 XServes and over 233 Gigaflops on 76 Power Mac G4s. But we find that the usability and reliability of the technology is as important as its performance. The ongoing dissemination of OS X, a Unix-based Mac OS, is providing the best tools of the Mac and Unix in one computing solution. With this development, Mac clustering is becoming the technology that will move parallel computing into the mainstream. See: http://exodus.physics.ucla.edu/appleseed/ and http://daugerresearch.com/