Actually this one is more like "Killing people in a fun and innovative way" :D

Deadly sodium

Suggestd Material:
1. Sodium powder (you can choose other group II elements in the periodic table)
2. Edible capsule


Steps:
1. Fill the capsule with sodium powder (or some other powder that you may have chosen from group II).
2. Give it to your unfortunate victim. (or is he actually fortunate, since life is an endless series of misfortune... :D)
3. Make him swallow the pill. (be creative here, tell him that it's a stress relieve pill or something, depending on the victim's personality and interests).
4. Escape the crime scene immediately (just stay away from your victim). Watch and record the entire bloody fireworks (literally) from a distance with a digital camcorder.


Note for non-chemistry people:
Sodium, and other group II elements are highly reactive metals. They are highly explosive when in contact with water.


Disclaimer:
No person or animal is harmed in the process of creating this post.
Any coincidence to anyone or any event is unintentional.
The author (i.e. me) would not be held responsible for any consequences if the torture/kill should be carried out.