Wow, Jeff - that’s a clever use of filtering! (I liked the earlier one that rearranged the columns, too. Cool.)
Here’s one I created a while back. The code isn’t nearly as tidy, but since it doesn’t access the dataset in its repeater (it uses an offset of item.index instead) it’s pretty fast. It also highlights the current day / selected day if either occurs in the current month. The UX is weird for choosing a new year (I challenge anyone to find it), but it’s based on how Android’s date picker does it.