How can I override the Calendar module's theme functions? I'm trying to override Calendar module's theme functions. Specifically, I'm trying to override template_preprocess_calendar_month() and template_preprocess_calendar_mini().

The override seems to work, but the problem is that the variables are processed/modified by template_preprocess_calendar_month() and template_preprocess_calendar_mini() before they reach the functions I implemented. 

I need access to some of the theme variables before they are processed. Is there a way to do so?
You can create your own custom module and define your own copies of these preprocess functions.

For this example we'll call your module mysite.

In your mysite.module file you would define:

mysite_preprocess_calendar_mini(&amp;$variables)
mysite_preprocess_calendar_month(&amp;$variables)


And then modify the contents of the variables in these functions as needed. Copying the existing preprocess functions might be a good place to start if you're not sure what you want to modify.

Check out the preprocess documentation for some more information about how this system works.