Some of us (hardware and software engineers, that is) are ancient enough to actually remember the MOS 6502. A photomicrograph of it's top layer is at right (as always, click to enlarge). The 6502 was the microprocessor at the heart of some of the early successful systems, such as the Commodore 64, Apple II, and Atari 2600. I remember it well and fondly: it was cheap, fast, and easy to design in. I incorporated it into several of my early projects, mainly as the processor for peripherals in a Z80-based system (because the Z80 could run CP/M, an early “operating system”).
These days, the 6502 is thought of more as an antiquity, something to be conserved in a museum. Which is exactly what these folks are doing! I was led to that site by a fascinating article on Bill Mensch, the guy who manually laid out the six masks used in manufacturing the 6502 – with no errors.