Top 10 Ways to Destroy Earth

Feasibility rating: 9/10

Hurled into the Sun
You will need: Earthmoving equipment

Method: Hurl the Earth into the Sun. Sending Earth on a collision course with the Sun is not as easy as one might think; even though you don't actually have to literally hit the Sun (send the Earth near enough to the Sun (within the Roche limit), and tidal forces will tear it apart), it's surprisingly easy to end up with Earth in a loopy elliptical orbit which merely roasts it for four months in every eight. But careful planning can avoid this.

This is impossible at our current technological level, but will be possible one day, I'm certain. In the meantime, may happen by freak accident if something comes out of nowhere and randomly knocks Earth in precisely the right direction. Earth's final resting place: a small globule of vaporized iron sinking slowly into the heart of the Sun.

Earliest feasible completion date: Via act of God: 25 years' time. Any earlier and we'd have already spotted the asteroid in question. Via human intervention: given the current level of expansion of space technology, 2250 at best.

Source: "Infinity Welcomes Careful Drivers," by Grant Naylor