Since magnetic LED creations have just about been beaten to death in a variety of fairly creative projects, I figured I'd stab that last bit of life out of them with LED shooties. An LED shootie is just like an LED throwie, except you shoot it out of an airgun or blowgun.
The design is simple, using only some paper and tape, you can transform any basic throwie to a shootie. Take the two prongs of an LED and put two 1.5v button cell batteries (or one 3v cell) between them. At the same time, a small rare earth (Because nobody can spell neodymium)
magnet is placed on the outside of one or both prongs of the LED. The whole setup should then be covered in duct tape to hold everything together.
In order to adapt it to fire from a blowgun, we need to put it inside a cone enclosure. Make a basic cone from paper and cut it off so that it fits in whatever sized tube you're working with. Cut off the very point of the cone so that the tip of the LED sticks out. Hot glue the LED and batteries in the cone and you're all set.
Uses for this include being a guerrilla graffitist and lighting up big metal things, or using it as a signal at night. I figure a streak of light shooting through the night would look pretty awesome.
Video below. It's hard to see for the camera, but it's plenty visible normally.