Simple 'ible, this. So you need a rack of hooks/pegs for your coats/bags/scarves/hats - simple.
Find an old bike chain, clean it thoroughly (put it in the dishwasher, soak it in hot detergent, or use other solvents), scrub it, cut the chain down to length (this is easy with a bike chain link tool (http://en.wikipedia.org/wiki/Chain_tool) and pop a screw through either end into your wall (using a wall anchor/wall plug if you're not confident in your wall material; I wasn't).
Find some small-ish S-shaped hooks (I got mine off eBay for a few quid; they're 50mm in length) and stick them in the links spaced out as much or as little as you like. Bending the hooks with pliers to exaggerate the 'S' might help you get the hooks closer to the wall.
For longer chains (maybe you want to do this in a building used by many people) I doubt it would be too difficult to have several lengths of bike chain linked together with screws going through the ends of the two chains you wish to join. Aim for screws supporting the chains every 50-90cm or so, I guess, to avoid too much pressure on the screws.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.