Pile Hitch
This is a convenient hitch when you have access to the end of the post. If you need a more secure hitch*, you can make it a Double Pile Hitch, shown below, by spiraling down the post an extra 360 degrees with the bight of rope before throwing the bight loop over the top of the post.

The way this hitch is made also makes it an ideal hitch for hitching at the middle of a rope.

*Referring to the diagram above, the Pile Hitch may be more secure when the bottom line is loaded, but since the method of tying lends itself to interchangeability of loaded ends, and when used on the bight either line may be alternately loaded, you should assume that a Pile Hitch has the security of the inferior configuration unless you're being very observant of your tying and use of the hitch.
Double Pile Hitch

Related Pages: Tumble Hitch, Midspan Sheet Bend, Timber Hitch on the Bight