The TurboGrafx-16, known in Japan and France as the PC Engine, is a cartridge based home video game console manufactured and marketed by NEC Home Electronics, and designed by Hudson Soft. It was released in Japan on October 30, 1987 and in the United States on August 29, 1989. It also had a limited release in the United Kingdom and Spain in 1990, known as simply TurboGrafx and based on the American model, while the Japanese model was imported and distributed in France in 1989.
You can browse and download most available games for free below, but you will need an emulator also to play them. For TurboGrafx I recommend http://www.emulator-zone.com/doc.php/pcengine/turbo-engine.html but you can use any emulator of your choice and even original hardware if you have the know how!