This is our easiest kit by far, but also the funnest--most fun. Man, funnest really should be a word. Anyway, this simple kit is a favorite among schoolteachers who want a simple demonstration of electrical circuits for their students, or just for budding hobbyists who want an ice-breaker project that they can't screw up.
Hey, the end product is practical too. We use a pure-white, ultra-bright LED that packs a whallup. The little flashlight is great for around the house, seeing behind tv stands and computer desks, and scaring away those alien monster things that are hurt by light.
These photos are of the flashlight built in an Altoids® Smalls tin with 3 coin-cell batteries, but the flashlight can also be made with a single 9v battery (which is much cheaper) by using a spare 9v Battery Snap.