I recently trawled through Wikipedia and collected a bunch of random national holidays, birthdays, and historical events for every day of the year and used javascript to make a dumb novelty calendar. Here it is in action: A few people told me they'd be interested if I packaged it into a widget, so here it is! Linking back to me is appreciated but not necessary.
Just copy/paste this into the <body> of your page and the widget will appear!
<script src="https://caminus.neocities.org/codezone/nationalday.js"></script>
This creates <div id="natday"></div> where you put the script.
You can style #natday however you'd like.
Alternatively, you can host the widget on your own site and customize it to your heart's content. You can add your birthday, an important holiday I forgot, or anything else you want! You'll notice the version on my homepage is slightly different than the one available here.
"05-17": "it's Squeaky's Birthday!",
<script src="nationalday.js"></script>