Not sure if they're even being made, but a large, bright-colored and/or reflective piece of material would be useful.
Not a typical one, but something of a very thin yet durable fiber. Something that when folded up compactly, would be very small, but when opened,
could cover a large area.
Look at a typical bed sheet for instance, and how small the packaging is. It'd be cool to pack something 5-10x larger into that same kind of space and
retain the same weight.
This material could then serve multiple uses. E.g. signal, wind shield (sand or dust storm), rain shield, sun shield, blanket (with some
improvisation), rope, clothing (i.e. to protect against the sun), a sail, etc. Whatever you feel the situation requires.
A typical brightly-colored bed sheet could even come in handy to do many tasks. And if needed as a signal flag, you could use some char (or something
else) to draw out a message on it (such as SOS or an arrow pointing in your direction).
Edit to add: Watch every season of Man VS Wild and Survivor Man (as well as other similar shows) and you'll get some interesting information on
survival. But don't just watch it, research it, understand it, and try it out, if possible, as the experience will be remembered better than trying to
recall something you only saw on tv.
I'm not saying these shows will give you everything you need, or that everything they display is the best way to do things, but you will learn a good
amount of stuff that is
Main thing is learning how to be creative and the use of improvising in order to get more out of something other than it's intended use.
on 7/26/2011 by BeyondPerception because: (no reason given)