A friend had outgrown some old jeans and donated them to me, knowing that I always have a use for such things. Since I live in a small room during semester, floor space is premium and shelf space is valuable, so I struck upon a way to clear things up a bit. A few minutes later and I had a place to keep all my shoes and socks :)
Step 1: Cutting the Slots
We're going to turn these jeans into something with lots of pockets. Plan out what size you think is appropriate or just do what I did and go at it with a knife and some scissors. Lay the jeans down on something you don't mind cutting if you're using a knife (ignore the picture - i used some cardboard to stop my knife damaging anything). The goal is to cut only the front piece of fabric while leaving the back intact - don't slice through the jeans entirely or you'll just end up with a bunch of denim tubes!
Step 2: Seal the Bottoms of the Pockets
To keep things from just falling through, I used hot glue to join the bottom of each pocket. It works surprisingly well on cloth (especially if it's very hot). As always, don't burn your fingers too many times. If you're concerned about the strength of the pockets, you can reinforce them with some cable ties, although I didn't need that.
You can also make the top section of the jeans into one big pocket for socks - perfect if you're like me and don't mind the odd mismatching pairs :P
And that's it - you're done!! Hang it in the closet and use that floor space for more important things.