@hm -- us: The dates are shown on hovering, thanks to CSS - no JavaScript is involved. Only the falling snowflakes are JavaScript animated.
In earlier years, we didn't always reliably check possible copyright issues, I've dug through the years 1994-1999 and 2012-2014 and removed those poems, stories, images... which might still be under copyright (which, in Germany, is 70 years after the death of the author / composer / painter ...). I have yet to do this for the years 2000-2011 and will try to get to this whenever I have a couple of minutes to spare. This is not high priority, though.
Edit: I've just noticed that the calendar does not work on some mobile devices (you will get a 404 error message), I'll have a look into that.