Ah yes, What is Idolm@ster you may ask?
It is a game from japan made by Namco where you pick one of several idols and lead her to stardom!Sounds stupid,you might say? Well,think of it like this: Namco made it, first of all,and second,its japanese, not American,so it doesnt look like the usual shovel-ware in america.
See this image here (I will post their casual outfits later)