Answer: GIMPS

Although SETI@home—the University of California, Berkeley project that has enlisted tens of thousands of computers across the world to analyze data from the Arecibo Observatory Radio Telescope and the Green Bank Telescope—most certainly put the idea of distributed computing on the map for most geeks, it wasn’t the first project of its kind.

Three years prior to the start of the SETI@home project was the Great Internet Mersenne Prime Search (GIMPS) project. Started in 1996, GIMPS was (and remains) focused on using distributed computing power to find Mersenne prime numbers—prime numbers that are one less than a power of two, and named after the French priest and polymath Marin Mersenne (seen in the artwork here). As of May 2020, the project has a sustained average aggregate throughput of approximately 1.17 PetaFLOPS (or PFLOPS) and has discovered 17 Mersenne prime numbers (bringing the known total to 51).

Since the GIMPS project, distributed computing has been used for all manner of projects including SETI@home (analysis of extraterrestrial signals), Folding@home (simulated protein folding, computational drug design, and other types of molecular dynamics), Bitcoin (decentralized currency), and even Electric Sheep (for animating and evolving fractal flames, which are distributed and displayed as screensavers).