Cambridge mathematics student Sam Hughes has provided a thoughtful critique and feaseability study about the various ways in which earth can be destroyed, from planetary collisions to a Vogon Construction Fleet. For those of you wanting to construct a Doomsday Machine, it has some handy pointers.
I am useless at making links, but googling "Sam Hughes Geocide" will get you straight there.
INTERVIEWER: Can you destroy the Earth?
THE TICK: Egad! I hope not! That's where I keep all my stuff!
Here you go:
Thanks a lot Jamtoy