A notepad holder that serves as a kind of inbox with a "you've got mail" flag that flips up when the lid is lifted.
It's a far from elegant, a pretty rough design mainly for my own use but serves its purpose well enough!
The pen holder is not overly secure, you could add a conical shaped holder at the bottom to improve this but I've just used some blu-tak which does the trick.
You may need to slightly widen the flag hole to loosen the fit if it's too tight.
The top flap is optional, it mainly just covers part of the flag at the top and sits held by gravity (if mounted vertically such as in the picture).
The right pivot was a press-fit in my print, but if loose for you then should only need a bit of glue, or you could try scaling it up a little.
I printed the base/enclosure with supports, but it might be possible to avoid them if your printer is particularly good with bridging. Cura's generated supports weren't too difficult to remove in my case.