A Space Blanket (aka Emergency Blanket) is a great thing to bring. Folds down to the size of a pack of smokes. tougher than a 2 dollar steak, I've used it as a wrapper over my sleeping bag when it got colder than I had planned, it's acted as an emergency rain shelter and sun shade. I've got an old military model, it's shiny mylar on one side, and OD Green on the other. Got some grommets around the outside edge, and it's a bit tougher than the very thin mylar ones, but still packs down pretty small.
Steve
Who thinks that a space blanket could even double as a sarong if the situtation required it