To combine with the "but did he build a cpu" thread, back-in-the-day the term project for MIT 6.004 was "build a CPU with TTL", with a very open-ended "performance race" extra credit project at the end. (At least one of the highest scorers went on build a network performance hardware company and sold it to Broadcom :-)

(If the "build a CPU" part doesn't impress, it was common to build an entire compiler toolchain to go with it; also it was long enough ago that a web browser really was a weekend project :-)