In The Groove 2 is the second iteration of a dance/rhythm series made by Roxor. It's extremely similar to Konami's Dance Dance Revolution and is the center of a massive gaming community for it's ability to play custom songs.
In the Groove (abbreviated ITG) is the first game in the In the Groove franchise, published by RedOctane and developed by Roxor Games, and first released in video arcades around August 30, 2004.