MorseCodr is a program for practising Morse code communication. You can connect to other users and send Morse signals that are automatically interpreted by the program. Once you become more proficient, you can reduce the amount of display and interpretation provided. It features Morse code tape display, dot/dash colouring, letter interpretation, and adjustable speed.
GeekOS is a tiny operating system kernel for x86 PCs. Its goal is to be simple enough for beginners to understand and modify, but realistic enough to be interesting and fun. The primary development environment for GeekOS is Linux or Windows using gcc, nasm, and the Bochs PC emulator.