Magnetic Field Paper
This is so cool! It will show you the magnetic field on items because there are individual cells in the paper with magnetized iron. I wish we had this in my science class!
There is no ink in this pen... and yet it writes, on almost any piece of paper, and won't smudge. It's a fully metal nib, so you can show off to your friends how you can write upsidedown and it will never dry out!
The magnets in this cool simple device are so strong that they work to project one ball bearing off the end like a gun. Although it's not going to kill anyone I still wouldn't point it at someone you like.