In the tradition of the Evil Overlord List: How To Destroy the Earth.
The Earth was built to last. It is a 4,550,000,000-year-old, 5,973,600,000,000,000,000,000-tonne ball of iron. It has taken more devastating asteroid hits in its lifetime than you’ve had hot dinners, and lo, it still orbits merrily. So my first piece of advice to you, dear would-be Earth-destroyer, is: do NOT think this will be easy.
For the purposes of what I hope to be a technically and scientifically accurate document, I will define our goal thus: by any means necessary, to render the Earth into a form in which it may no longer be considered a planet. Such forms include, but are most definitely not limited to: two or more planets; any number of smaller asteroids; a quantum singularity; a dust cloud.
The site then goes on to list possible methods ranked by feasibility.
(via Cruel Site of the Day [archive.org])