It's called Save the Date. It initially appears to be a visual novel dating sim, but it isn't. At all. It's really best to go into it blindly, so I'll try not to spoil it, but it's really, really funny, fantastically written, and provides really great commentary on storytelling (esp interactive storytelling). (Tip: keep playing after each bad ending. Try to avert them. You will progress.)
It's short, it's free, and it's quality. So much quality.