Koge*2 House is the circle of Koge Donbo, who is currently very popular, being
the main manga illustrator for Di Gi Charat. I'm pretty sure she's a high-end circle.
("High-end" means a circle or doujinshi that is made by an artist that is a popular professional artist, I think.)
This is the only high-end circle I've bought stuff of to date, not because I don't love high-end art, but because most of the
professionals make H doujinshi. :P But it was interesting enough that Koge Donbo had dipped into HP,
so I sprang for it. There's also at least two doujins following the one below on the same theme, although both are smaller.