Catholic Answers
Hangman's Noose
You don't have to be an executioner to appreciate this noose.  Nor do you have to have the traditional eight coils.  This is actually a very practical, strong, and secure noose, but may become difficult to untie if pulled hard.

To make it, start with a "N"-shape of rope, with plenty of extra rope off the bottom of the "N" (nevermind the direction of the "N").  Keep wrapping tight coils spiraling up the outside until you're satisfied and tuck the end of the rope through the top eye.  Pull down the bottom eye to form the loop and trap the tucked end of rope.

This knot bears some resemblance to the
Uni-Knot commonly used in monofilament line by anglers.

If you ever came upon desperate times in the woods and needed to snare some game but only had rope and no snare wire, you might consider using the sturdy Hangman's Noose.  Don't use the noose itself, but rather run the standing part of the rope through the noose to form a running loop.  You can adjust the size of the noose perfectly to make sure your running loop isn't too stiff or too sloppy.  Use light grasses to tie the loop to bushes or twigs to keep the snare in place.

The Hangman's Noose can also be used as a means to put extra mass at the end of a rope to aid in throwing a line.  Of course, the loop can be made very small for such a purpose.  When you want to untie it, just pull the loop all the way through and the knot will disappear.

Related page:  Gnat Hitch