While upgrading to the CS2008.5 SDK I also upgraded the CS2007 calendar control to work under CS2008.5.  There are still several issues that need to be addressed, but I have the control working on this site.  The next step will be to remove the ComponentArts DLL requirement so that the control can be distributed.  If I have time this week, I may be able to have something by next weekend.  I'll have to see how things go.  Until then, take a look at the Calendar page and let me know what you think.  This post should be visible on the calendar as I placed a [cal/] tag at the beginning of the post.