I want to understand stuff, mostly low-level things. The book of Shimon Schocken and Noam Nisan - The Elements of Computing Systems - helped a lot in that respect.
- Understand computer graphics by writing a software renderer from scratch.
- Reverse Engineering the BIOS (how does Linux replace the BIOS routines), Coreboot
- Architecture of (modern or not so modern) GPUs (trig. algorithms and such)
- Superseding the school and university system with self explaining, interactive learning modules, attached to a peer-to-peer hosted community system. CodeWars is a first step in that direction, paired with replay of code.