Circus is a Japanese game developer that is most well-known for it's Da Capo series. However, it has released a number of other titles.
Lately I've been heavily into Da Capo thing, watching 2 seasons of Da Capo anime, then moved on to Da Capo II and I've just finished watching the first 13 episodes. The latter part is scheduled to air in April,2008. Meanwhile I suggest reading the article from Gsmagazine, issue #1,2008 which deals with the latest installments to the series.