Nie dürft ihr so tief sinken, von dem Kakao,
durch den man euch zieht, auch noch zu trinken.
(Erich Kästner)

Only few people are really willing to implement an own operating system, at least compared to the people willing to implement an own textadventure. But there are projects. Like MikeOS. A nice little OS with an elementary text editor, BASIC interpreter and an implementation of Hang Man.

Nothing special. But nice.