This is a simple flash light. All you need is a 3D printer, soldering iron, pliers, two AA batteries, a 10mm LED, piece of wire and shrinkwrap or electrical tape. This design is based around a 10mm white super bright led: https://www.sparkfun.com/products/11118. This design doesn't need a resistor as it only draws about 3/4 of its max current when hooked up to the batteries. If you plan to use a different LED measure the current draw. If you have any questions about assembly please ask.
I will post a design based around 4 5mm LED's next. Be patient.
Enjoy!

Step 1: Download Files
Step 2: Slice files (normal settings, no support)
Step 3: Print Parts
Step 4: Gather 2 AA batteries, piece of wire, 10mm LED https://www.sparkfun.com/products/11118, shrink wrap
Step 5: Bend the positive lead of the LED (Longer lead) as shown in the picture. This is where the positive end of the battery will touch.
Step 6: Bend the negative lead out of the way and re straighten, solder a wire to the negative lead (shorter lead).
Step 7: Either electrical tape the negative lead wire solder connection or shrink wrap it.
Step 8: Insert Led/wire assembly into housing. Wire should line up with the cutout that runs the length of the housing. Insert batteries and determine where to cut the wire and strip the end so that it will touch the negative side of the battery.
Step 9: Strip and cut the wire. Bend the wire into a little circle for better contact. Bend it slightly upwards so that it's not in contact until the endcap pushes on it.
Step 10: Screw endcap until LED illuminates. Put some lubricant or grease on the threads.
Step 11: Unscrew endcap. If LED doesn't turn off you need to tweak the wire/negative battery connection.
Step 12: Enjoy your now illuminated world.