Hatsune Miku: Project DIVA (初音ミク -Project DIVA-) is a series of rhythm games created by Sega and Crypton Future Media. The games have appeared on the PlayStation Portable, PlayStation 3, Nintendo 3DS, iOS, Sega RingEdge and PlayStation Vita platforms. The series currently consists of 5 main titles and 3 spin-offs. The series primarily makes use of Vocaloids, a series of singing synthesizer software, and the songs created using these vocaloids most notably the virtual-diva Vocaloid Hatsune Miku. The game is the first video game to utilize the Vocaloid software developed by the Yamaha Corporation.
Source: Wikipedia, "Hatsune Miku: Project DIVA", available under the CC-BY-SA License.