It was a long time ago since I last used a classic wall paper (i.e., a picture in the root window). I realized I rarely looked at it and the aesthetic rapture it provided would be better served in an actual painting, not in a passing-by location such as the root window.¹

However, you can actually make your root window serve an actual use with root-tail.

Root-tail displays log files in the X root window or another window.

Though it was originally designed to display a rolling log file, it can of course be used with any file.

I use Remind as my calendar, I pipe it to root-tail to get two weeks displayed in the root window:

remind -c+2 -w150 "$HOME/.reminders" | tr -d '‎' |
        root-tail -i 10000 -fn '-*-fixed-medium-*-*-*-15-*-*-*-*-*-iso8859-*' \
        -g 1480x275+0+0 -,green,

This way I always have a glimpse at my appointments when starting my computer, so I hardly ever get surprised by one I didn't remember and didn't prepare for.

¹Some use transparency on their terminal windows so that they can see some of their background. But why throw stones at them? We also have almost as crazy idiosyncrasies.