The Hangman's Knot is also known as a Noose or (to Knife Enthusiasts!) as a Chris Reeve Knot. Its easy and effective, and like any other knot, can be adorned with fancy beads. The big benefit of it is that it can be done with almost any length or type of cord, and if using paracord, you can retain the inner strands- very handy in a survival situation.
Step One- Fold the cord into an "S" Shape.
Step Two- Fold the lower part of the "S" across the other two strands.
Step Three- Wrap the cord around the other cords several times. Do this until you only have a few inches left, or you have closed the loop at the bottom (left in these photos).
Step Four- When you have wrapped the end around the loop several times and gotten the length you want, put the loose end through the bottom loop.
Step Five- Pull the whole thing tight and it should look like this! Remember you can make it as long or as short as you like, depending on how much cord you want to carry with you.