Tarp camping is a useful tool for fastpacking. It provides light-weight shelter from the elements and is very flexible in application. The equipment used for the following tarp designs include:
1) 5' x 8' sil-nylon tarp from Oware
2) shepherds hook titanium stakes with orange hook coatings
3) 1 mm cord that came with the tarp
Setup in the backyard is easy compared to the trail. The ground is soft and there is plenty of flat space. It should be noted that a good tarp shelter will need to be able to deal with obstacles such as constrained spaces, rocky ground, uneven surfaces. slanted surfaces, etc. But in a lot of cases you should be able to use some of these things to your advantage. I can think of no better tent stake than a tree.
The designs shown here are my first attempts at how I might set up a tarp to protect me from driving rain, and or wind that is coming from one or two directions. This setup is intended to be combined with a water resistant or waterproof bivy to keep your sleeping bag dry. I do not consider it important to have the foot of my bivy covered by the tarp(since my bivy is supposed to be waterproof). I would consider it a successful application if the top half of my bivy doesn't see direct rain or wind impacts.
The first design is the good old fashion lean-to but with a foldover on one side. This should protect you from one direction very well, and give you some more protection from one of the sides. This would not be ideal for a swirling environment, but it does allow some space to sit up.
This is all good in theory, but until I actually have to deal with inclement weather on the trail it is going to be tough to evaluate the designs. Most likely the condition I face, and the terrain or obstacles that I have to deal with will determine the design I use.
The tarp is 7 oz. The stakes are 2, and the cord is another oz. All together I think this is about 10 oz, which is a pretty cheap(in terms of weight-which is the fastpackers currency) insurance policy for crummy weather.