I tend to be interested in low level programming and distributed systems.
Recently, two of my projects were bsfs, a unix-inspired filesystem format made from scratch, and boot, a x86_64 bootloader capable of booting kernels off of a bsfs filesystem. These two experiments are really inspiring to me and I would like to explore the prospect of making a full-blown system further.
One of my favourite aspects of low-level/systems programming is how the programmer typically gets to design abstractions over how the hardware works into a coherent and portable interface.