Hacking get_calendar?

Yes, I have the same need. It would seem convenient to add a parameter to the get_calendar() function besides the ability to show a full or abbreviated month name.

I have categories with a custom design for each category and I would like to keep vistors within that category even if they click on a date in the calendar. Has anyone come across a calendar that does this or do I have to write my own plugin?

I really need this too. I want to use the built-in WordPress post dates for an event calendar rather than the unreliable custom functions of the existing calendars.