Found this interesting article at Sam’s Archive, where Sam works through a set of methods for destroying Earth:
Destroying the Earth is harder than you may have been led to believe.
You’ve seen the action movies where the bad guy threatens to destroy
the Earth. You’ve heard people on the news claiming that the next
nuclear war or
cutting down rainforests or persisting in releasing hideous quantities
of pollution into the atmosphere threatens to end the world.
The Earth was built to last.
He then goes on to describe a series of possible solutions to the
problem, giving a feasibility rating and time estimates on
implementation. Rather silly but also rather fun.
Ties in rather well on my small article on Impact Calculation.