Guitar Hero is a popular guitar simulation/rhythm game series developed by Neversoft and published by RedOctane and Activision. There are currently four games in the series, Guitar Hero, Guitar Hero II (for PS2 and Xbox 360), and Guitar Hero III. An expansion pack for GH2 (Guitar Hero: Rocks the 80s) was released on July 24, 2007 for PS2, being the last game in the series to be developed by Harmonix before it was passed over to Neversoft for Guitar Hero III, Guitar Hero Aerosmith, Guitar Hero World Tour, and Guitar Hero Metallica. In addition, Activision has licensed two toys bearing Guitar Hero name: Guitar Hero Carabiner and Air Guitar Hero Rocker.