A properly erected rain tarp can make all the difference in the world if you are struck camping during rainy weather.  If you have a tarp, you can sit, cook or relax in relative comfort in the foulest of weather.  If you don't, you're going to be spending a lot of time in your tent.

Some campers carry a lightweight 10'x12' tarp made of ripstop nylon and that has brass grommets around the perimeter.  Although it is expensive when compare to the woven "tarps" available, it packs down to a very compact bundle and weighs next to nothing.  If you are traveling with a larger group, you might choose to carry two of these.

The most common method of erecting a rain tarp is either "lean-to" style, sloping front to back; or a peaked "tent" style.