Your fridge magnets suck. At least compared to the new magnet being built at the National High Magnetic Field Laboratory, which is set to be the most powerful in the world. It'll be a pulsed electromagnet that will reach a power of 100 tesla when it's complete, which is a whopping 67 times more powerful than the magnets in a typical MRI.
The super-powerful magnet will be used to "test the properties of newly discovered high-temperature superconductors like iron oxyarsenide, which may improve the performance of MRI machines and high-voltage power lines while lowering their cost." Well, I'm not going to argue with that. I just want to know how many VHS tapes you could erase in one shot with this thing.