Step 1: Gather Materials/Tools
Flat magnet, the kind that many places give away for free as advertising.
Step 2: Preparing the Magnet
To remove the paper try soaking the magnet in water. The paper should peel off easily while wet. You do not need to get all the paper off. This will give the duct tape a good surface to adhere to.
Then you need to fold the magnet in half. Cut the magnet along the crease you made from folding it.
Put the two pieces together magnetic sides facing each other.
Step 3: Sticking
Step 4: Trimming
Step 5: Testing
I have made several of these to use when I am teaching out of a book and need to flip back and forth quickly. I make them much smaller. They don't crease the paper like paper clips or fall out like conventional bookmarks. When not in use I stick them to the refrigerator.
Note: As I was finishing this instructable I saw that someone else posted the exact same project on the 8th. So I lose points on being original, but since I took the pics and did all this work I decided to go ahead and post it.