I'm another couscous fan - no other dried food that I know of gives you more bang for your buck. The required amount of water (and therefore fuel to boil it) is minimal and no simmering required.
For example a typical serving of flavoured couscous (Supermarkets own brand or "designer" stuff like Ainsley Harriott's) require you to bring about 150ml (about a third of a pint) of water to a boil, chuck in the couscous, stir with optional olive oil and remove from the heat. Put the lid on your pot, wait 10 minutes and voila! - I also like to stir in some tinned fish in tomato sauce at this stage.
Incidentally, Ainsley Harriot does other dried ready meals like Bulgar Wheat and Dhal Lentils etc (No relation or connection by the way). These typically require about a 20 minute simmer though - I tried the Spelt one last weekend and it was dee-freakin'-licious!!