click here to download a small zip file (19K) containing all you need to add a calendar to your hot list. Neat (~_~)
It shows three months to a view, allows Sunday or Monday start to the week, and has three colour schemes. No doubt the experts will be able to edit the style sheets to add their own.
There is also an option to display the calendar in Dutch.
Note: Non-Opera users can also open the file and see how it works, as it is just HTML with some style sheets, but they obviously won’t be able to install it as a panel (at least I presume that there is no way to do this).