49 grams and five minutes that may Save your Life: Follow the instructions here: http://www.theultralighthiker.com/hole-less-ponchoshelter/
As you can see you can sit down against a tree in front of a fire wearing it and be perfectly dry – with a little help from your small dog, Spot!
See also: http://www.theultralighthiker.com/more-fun-with-sticky-tape-ultralight-mylar-vest/
Actually you can buy similar ponchos now: http://www.theultralighthiker.com/if-you-could-only-carry-two-things-in-the-bush-what-would-they-be/ but it is much more fun to make your own.
Next I will make an inflatable mylar quilt weighing approx 100 grams and about R4.0