If you know a music or math teacher, or even a mathemusician, ask them how wide their writing implements are and how far apart they like their lines, and you've got a great gift idea.
The OpenSCAD file is fully parametric, well-commented, and easy to modify. You can change the number of lines, the distance apart, pen diameter, pen grip length and thickness, amount the grip "wraps", extension from handle, extension thickness, handle height/thickness/length, and even handle curve radius.
With a little tweaking of the parameters, you can set it up for chalk/blackboards, street chalk, pencils, different dry erase markers, crayons, or just about any other cylindrical writing implement.
I plan to add a keyhole-style mounting system because it also seems to serve quite well as a pen holder -- and if you hold the pens at the cap, you'll never forget to recap them because they won't stay held if you don't.