There are a fairly large number of prepared foods that are not specific to backpacking (i.e. available in normal grocery stories or super WalMarts) that can be cooked by only adding boiling water to them in a normal ziplock type freeezer bag and allowing them to stand for 5-15 minutes or so. That includes many of the items listed below (Lipton side dishes, macaroni and cheese, stovetop stuffing). Backpacker.com has lots of information about that in their forums. Those have been kind of interesting to experiment with. Add some meat to those from a foil pouch at the time of preparation and you have something that is very easy to fix, requires little or not clean-up, yet is not very heavy.
In planning the food, I found this site that listed calories per ounce interesting:
http://www.oc.edu/staff/phil.heffing...odCalories.htm
In keeping with the spirit of maximum calories per ounce, I really like Ultralight Joe's Moose Goo. It is easy to make and tastes good. However, I recommend you allow it to sit a day or two before using it. I noticed the consistency and taste improved after a day or two. I guess it must have been the corn flour (note it is NOT corn meal) absorbing the honey and peanut butter. I have not tried it in really hot weather, but it held up well even in 70-80 degree type temperatures. However, I understand it is a problem at low temperatures, since it becomes too stiff to extrude from a squeeze bottle.
http://www.ultralightbackpacker.com/moosegoo.html
Bon appetit!! Have fun experimenting!!