DeSmuME (formerly known as YopYop DS) is the first Nintendo DS emulator that can run both homebrew and commercial game ROM at a playable level for Windows, Linux and Mac OS X. It was written in C++ and released as open source freeware.

For any video game PC emulator player, if you already knew the best PSOne emulator is ePSXe, then you also must know the best one for PlayStation 2. Right, that is PCSX2, an open source and free PS2 emulator for Windows, Mac and Linux.

If you're a web developer or learning web programming languages, you must found that: every time want to perform local debugging, testing for your web app/code on a new OS or another PC, you has to set up and configure the whole AMP (Apache, PHP, MySQL) web development environments from scratch, which is absolutely boring.

TeboCam is a very powerful, interesting and practical freeware camera enhancer, developed by TeboWeb from United Kindgom. Through the surveillance of camera content, when the scene changes, it will automatically take a screenshot and send it to the specified address (local or network space) via FTP, Email. In short, TeboCam enables us to make our camera into a powerful security surveillance monitor.

Citra (AKA: eMu3Ds) is currently the only still living 3DS emulator for Windows, Linux, Mac and Android platforms. It is written in C++ and open source, and can run partial 3DS classic games better. Although supporting all HD 3DS games has a long distance, yet from the official news we are sure this is not far off.