It can go a lot deeper: take the Tokyo University CPU project as an inspiration: You need to use FPGA board to build a machine that runs an OS ported to this a

It can go a lot deeper: take the Tokyo University CPU project as an inspiration: You need to use FPGA board to build a machine that runs an OS ported to this architecture, which has a high level language with a proper tool chain, all built by yourself. Then you use the language to build DB, Webserver and such.