Oreimo was controversial when it was first shown, and i’ll be posting a review on it in due course. One of the things it does right is its opening sequence, with each episode having its own unique visuals (and the song is pretty catchy too!).
While searching for a video for this week I stumbled across one that compares each opening so you can see just how different they are.
[Edit]: Youtube, being its overpossessive self, took down my videos. New order is the full length song (including original OP) followed by the OP comparison video.