I got this off some website but I forget where.
What you do is tie a noose around your neck with a sharp wire such as piano wire.You tie the end of the wire to a bridge or something strong that will not give you to your weight, like a bridge or something. Make sure that the piano wire is strong enough to hole your weight.
Then, put the piano wire noose around your neck. Superglue your hands to your head and wait for the glue to dry. Jump off the structure. If you did it correctly, the piano wire should effectively decapitate you, but your hands will be stuck to your head. This way, whoever discovers your body will see it and it will look like you pulled your head off of your body with your sheer manliness. Imagine how badass you will seem during the open casket funeral.