5.5 Gram Backpacking Stove

Backpacking stoves are insanely expensive, the first hit I got on that search was an 8.5oz (250g) stove for $75.00 (€53).  You can make a 0.2oz (5.5g) stove at home, from two aluminum cans, for free.

Actually the free part was somewhat misleading, you actually will need to pay $0.25 for the quarter.  The stove runs on alcohol, depending on the type your efficiency will vary.

Materials:

• Two aluminum cans.
• Pushpin
• A Quarter
• A sharpie
• An utility knife.
• A textbook.
• A ruler
• Tweezers / needle-nose pliers

Optional (aesthetic):

• Sandpaper

Procedure:

1. If you are going the sandpaper route, sand off the bottom inch of the paint on the cans, this is much easier to do while the cans are full and still have pressure, otherwise they will dent while you are sanding them, which is not good for the end result. 
2. Open your book and lay it on a table so when the sharpie is placed on it, the tip of the sharpie is one inch above the table.  Open the sarpie, and with it's tip extending past the edge of the book, rotate one of your cans so a circular line is drawn around the can one inch above the bottom.  Repeat for the other can.

   

   Sanded Can With Mark

   
   

3. Use your utility knife to cut along the circle for both cans, this is easy to do if you use a similar method to marking the cans.  The blade should have a large area where it is touching the can to produce the most work as you rotate the can.

   

   Cutting The Can
   

4. Continue rotating the can until either (a) the knife breaks through, or (b) you get tired; in the case of b cut in to the can along the indentation made by the knife and begin to pull the can apart, it should separate cleanly where you scored the surface.

   

   Completed Cans
   

5. Crimp one of the cans using tweezers (or needle nose pliers).

   

   Crimped Bottom Half (Inner Part of Stove)
   

6. This can should now fit inside the other, slide the tops together, then push evenly until the cans slide entirely in to each other.  If this is not done carefully one of the cans may split and you will need to make another.  From here on I'll call with the most visible surface area the outer can; the other will be the inner can.
7. The outer can may extend past the bottom of the inner can, if this happens roll the bottom on a hard flat surface and the outer can will form a lip over the bottom.

   

   Before and After Rolling Bottom Edge
   

8. In the top center of the outer can punch five holes closely together using the pushpin. You should be able to cover all of them easily with the quarter.

   

   Filling Holes

   
   

9. Around the outside of the top can punch eight holes equadistant from each other, this is easier if you begin by punching two that are opposite each other.

   

   Finished Stove
   

10. Your stove is done, to fill it pour alcohol in to the middle, the five holes you punched should easily allow it in to the can.  Cover the holes with the quarter.  
11. To light you will first need to heat up the alcohol inside until it turns in to a gas and begins exiting the jets.  I do this by pouring a small amount of alcohol on a lid lighting it, and placing my stove in the lid.  A tealight might work as well.
12. If lighting is difficult, add more jets.

Conclusions:
I have read some articles about the efficiency of these devices, and it appears that they can heat water at the same rate as more conventional stoves, however they tend to use more fuel, which may make them less desirable while backpacking.
You may want to experiment with the number of holes. or the height of the cans.