I have done many projects, here are a few of my favourites:

• RhysOS
  A 16-bit operating system written in C for the 8086. Tested on my Toshiba t3100e. Implements: bootloader, filesystem (FAT-12), VFS, graphics and text modes, CLI. (Assembly, C)
• RhysLang
  A programming language that can compile into x86 assembly, from 8086 assembly up to modern x86_64 assembly. (Assembly, Perl)

• DMachine

  An equivalent of distrobox for Mac OSX docker containers. (Perl)

• Netkit SDK

  A program to generate Netkit-JH labs with code. (Perl)