http://lass.vs.rosebleu.jp/From what I know, it appears two visual novel companies (Lass, makers of 11eyes, and Rosebleu, the makers of Stellar Theater) are collaborating to make this awesome looking 2D fighting game. My mind is officially blown.
I'll probably be maining Yuka on the Lass side.
EDIT: Then again... I hope it's not another April Fools joke. I discovered this only today, I don't know when exactly is it posted.