Atari 2600, C64, Python, 3D engines and rock'n roll
All information from hardware sensors on your Mac
Windows XP reimplemented on Nintendo DS
Highly portable Gameboy Color emulator
Simple 8-bit Assembler Simulator with Angular.js
E-UAE Amiga emulation PowerPC JIT compiling implementation
A low-power ISA design and simulator for a 2010 IEEE competition
z390 Portable Mainframe Assembler and Emulator
Java-based instruction level emulator of MSP430. Code on github.