I'm not in school anymore, but these notebooks (almost) make me wish I were!!
Paper (1-sided non-confidential paper rescued from the recycling bin at the office, or to be schmancy, use actual store-bought filler paper!)
Thick corrugated cardboard (from shipping or paper boxes)
Scissors or an x-acto knife
Split rings - mine are called "Loose Leaf Book Rings" when I order them
3-hole punch (for the paper) and a 1-hole punch (for the cardboard - though you could try to use the 3-hole punch!)
1) Assemble your supplies.
2) 3-hole punch your interior paper.
3) Measure and cut your cardboard covers. I recommend your cover dimensions be 1" bigger each way than your paper, so it can hang over on each side (so for the full-size version, covers are 9.5"x12"). Round the corners.
4) Using a hole-punched page as a template, mark where the holes need to be punched on the covers. The split-rings I have are 1" diameter, so I put the hole a little more than 1/2" in from that edge.
5) Hole-punch the cover.
6) Assemble your pages using split rings.
You can easily add or remove pages by just opening the rings again (hint: academic handouts or pretty magazine pages)! Either leave it as-is for a more industrial look, or decorate with whatever you like! You may notice that the paper has "graph paper" printing on it -- I just downloaded some free graph paper from the internet and printed a few sheets, since I love graph paper, and filler graph paper is ten gajillion dollars a pack.
I also made a smaller, 1/4 page version, and cut out little file-folder tab pages from cardstock to divide different sections.
*note: Those reams of paper are not related to this project.