This is absolutely fantastic, well done!
If you're not done playing with it, you can make it dynamic so it's always accurate, haha! Show the smallest "uncompleted" unit of time available with a fallback for December 31st evenings where tintin simply says nothing...
At night: select the week.
Also end of the week: select the month.
Also end of the month: select the year.
Also end of the year: fallback.
That's a good idea -- it'd preserve the intent of the meme, which is to always be conveying "it has not been as long as it feels like based on events".
As-is, if I visit and see "what a day / it's Friday", that's kinda missing the point.