Open-source KVM software

TCP port scanner, spews SYN packets asynchronously, scanning entire Internet in under 5 minutes.

NVIDIA Linux open GPU kernel module source

Klipper is a 3d-printer firmware

H2O - the optimized HTTP/1, HTTP/2, HTTP/3 server

xv6 OS

Direct Memory Access (DMA) Attack Software

Terrain rendering algorithm in less than 20 lines of code

open-source IEEE 802.11 WiFi baseband FPGA (chip) design: driver, software

Build android apps without any java, entirely in C and Make

Storage Performance Development Kit

Prime number projects in 100+ programming languages, to compare their speed - and their programmer's cleverness

ldd as a tree

Linux Device Drivers 3 examples updated to work in recent kernels

The open-source files comprising Leap Motion's Project North Star AR Headset.

Linux Library for low speed IO Communication in C with bindings for C++, Python, Node.js & Java. Supports generic io platforms, as well as Intel Edison, Intel Joule, Raspberry Pi and many more.

CaribouLite turns any 40-pin Raspberry-Pi into a Tx/Rx 6GHz SDR

Horizon is a free EDA package

ABC: System for Sequential Logic Synthesis and Formal Verification

(Unofficial) Firmware Upgrade for Dyson V6/V7 Vacuum Battery Management System

Liferea (Linux Feed Reader), a news reader for GTK/GNOME

Cross Platform Fixed Point Maths Library

Parallel solvers for sparse linear systems featuring multigrid methods.

Code for simulations on YouTube

A parametric aircraft geometry tool

Magic VLSI Layout Tool

Tools for people envious of nvidia's blob driver.

Build userspace NVMe drivers and storage applications with CUDA support

XSDL - X.Org server ported to Android using SDL.