Bowline

A commonly used knot to tie a loop in the end of a rope. It has the advantage of not jamming, compared to some other loop forming knots (for example when using an overhand knot on a large bight to form a loop).
Form a small loop (the direction is important), and pass the free end of the knot up through the loop, around behind the standing part of the rope, and back down through the loop.
A chant used by many to remember this knot is "The rabbit comes out of the hole, round the tree, and back down the hole again", where the hole is the small loop, and the rabbit is the running end of the rope.
In the same way that a Left Handed Sheet bend is a Sheet bend that has the running end of the rope coming out of the wrong side of the knot, a cowboy bowline is a bowline that also has the running end of the rope coming out of the wrong side of the knot. It suffers the same problems as the left handed sheet bend.

Tip. Don't be afraid to use this knot to form a loop of any size in rope.
Tip. To quickly identify if you have tied the Bowline normal or left handed, check to see that the running end exits the knot on the inside of the loop.
Tip. For added security, finish the knot with a stop knot such as a Figure of Eight knot to remove any possibility of the Bowline slipping.
Tip. If you use this knot in a man carrying situation - perhaps a rescue where a harness is unavailable - then you MUST use a stop knot as mentioned above.