This is one of the smallest flashlight that you can make.
you dont need special tools, casing,switch,etc.
its simple and quick project that you can make just following this steps :D

Step 1: Parts

You will need :
1x LED ( any color,white is brightest)
1x cr2032 battery ( 3v battery, button cell)
some glue from glue gun
lighter
scalpel

Step 2: Building

First you gonna do is to cut small peace of glue.
than put anode of LED to positive side of battery. Put peace of glue on anode and start heat it with lighter ( for 2-3 s) . when you melted glue just ake scalpel and push it so that glue can stick to battery.

Step 3: Finish

when you finish this just bent cathode back.
when you want to use it just push cathode to - end of battery and light comes....

one note, my LED is glowing ok but battery is half discharged ( i scrap 50 batterys from old motherboards so half of them are discharged and half is around 2.8 v )
this flashlight can work as mouch as led throwie (1-2 weeks constant, or on daily use from bed to bathroom = 1 year)