I agree that in this particular instance, the original poster is probably best off just copying, pasting and modifying the calendar html. It’s only one month, with a few days worth of posts. But that said, what he’s asking for isn’t nonsensical.
I’ve got a historical “blog” for which I’d like pretty much the same thing. The site is a series of letters written on particular days. WordPress works well for managing and displaying this kind of information. The entire collection of letters only spans a few months. I’d like to be able to have just the relevant months displayed in the sidebar, with the current letter (or letters, in the case of search results) highlighted on the calendar. Such a UI would allow users to easily navigate the entire collection, and the same time underscore where the current document falls in a series of historical events. For this project, the current date doesn’t matter. Nor do future posts… there won’t be any. Something like get_calendar(1965, 7) would be a very handy function for me.
