Step 1: Materials? Materials.
@ 1 Plastic Dinosaur! I used a Ceratosaurus model, mostly because it had two feet, and I had two magnets. You could probably use a four-legged dinosaur, but you would have to alternate the magnets between the legs somehow. Also, I encountered a problem later with the fact that the two feet weren't exactly level, which may prove a problem if you're trying to stick it on a fridge, but the tail helps.
@ 1 Pair of Broken Earbuds, I'm reasonably sure all of you have one of these. I have at lest four pairs where one "bud" died, so I've moved on to over-the ear headphones... (Also, check out These Ones!)
@ Super Glue, Epoxy, or another glue. You might be able to use plastic cement, but I haven't tried yet. The most important thing is that there is a strong bond.
@ Pliers for Smashing! I used a Mini Quasi-Leatherman. A Full sized one may be overkill. Also, it includes a knife for a later part.
@ A Trashcan. You'll be glad, trust me.
Step 2: Earbud Deconstruction!
Good job, you just got yourself one strong little magnet, out of something you were going to throw away!
Step 3: Fancy Footwork
Edit: Dr. What has pointed out that a dremel would accomplish this step a whole lot faster and more easilly, and there's less chance of you slicing your thumb. In Half!