Ways to destroy the world

Just a fun little topic about apocalypses, inspired by the lack of world destruction this year. We survived another one!

Anyway, for anyone considering the possibility of imminent destruction, in apocalyptic RPs, how do you want the world to end? I've got several ideas, which vary a bit by genre, but all pretty fun.

So here we go...

Sci fi apocalypses:

1. World War III. Possible as early as last century, a war of nuclear annihilation can wipe out all civilization on Earth. There will likely be some survivors, but the world as we know it would end. This is what happened in the Fallout universe, as well as Terminator, and makes for some really awesome post-apocalypse RPs.

2. The Zombiepocalypse. Possible within our own lifetimes, assuming Earth scientists research biotechnology and some crazy mofo genetically engineers a Resident Evil style virus that either animates corpses or alters humans into something less than human and hungry. One of the more popular apocalypses in the media currently.

3. The Robot Uprising. Research into artificial intelligence succeeds, but the artificial intelligence for some reason decides to turn on humanity... either out of self-defense or because they find humans abhorrent. Been around in one form or another since Frankenstein, and also the foundation of such movies as Matrix.

4. Huge freaking asteroid. Just as it says, a giant freaking asteroid such as the one that wiped out the dinosaurs crashes into Earth, civilization wiped out. Survivors make up a new world.

5. Alien invasion. They're either here to conquer or eradicate, but all civilization on Earth is doomed, as there is no way human technology can compete with the advanced weapons of the aliens.

6. Sun go boom. Won't happen for another few billion years in Sol, but it can be used on some non-Earth planets full of aliens.

I don't consider the icecaps melting or ozone layer decaying to be viable apocalypses, although some people might.

Fantasy apocalypses

1. Ragnarok. The war between fantasy gods basically eradicates all life on said fantasy world.

2. Zombiepocalypse REDUX. Rather than a virus, it's some magical plague invented by a hideous necromancer.

3. Vampires get hungry. A form of the zombie plague, but instead subscribing to the concept of vampires turning people into vampires after they kill them. Vampires are much smarter and more dangerous than zombies, so this would be much harder to survive.

4. Orcish invasion. The Honorable Warrior Guy Kingdom whose sole job is to keep the orcs contained... falls to a mighty Orcish warlord. With Gondor destroyed, nothing will prevent the Urik-Hai from wiping out all life on Middle-Earth. Initially proposed by Tolkien, obviously.

5. Return of the Age of Magic. Magic comes back, changing the world forever. Yes, I stole this idea from an interest check I read, but it looked interesting. It's been done in the Shadowrun universe, too.

So what are some other good ways to destroy the world?

Sci-fi;

• Resource depletion. Humanity expands beyond a point resources are capable of supporting and we happen to have moral quandaries with killing off civilisation to restore balance. Chaos ensues. Earth is exhausted, unable to return to it's previous state and is currently capable of supporting about 5% of all humanity.
• Universal Corrosion. Rather than zombies another unstoppable virus targets earth and effectively destroys the fundamental materials we use to build things; causing chaos and panic worldwide and humanity basically kills itself in the process.
• Digital AI Uprising. Like robot uprising, except not physical robots but all our machines turning against us... Override our systems and throw our own nukes at us.

Prolly more. Maybe later.

EDIT:
Fantasy:

• Succubi with aids.

Sci-Fi:

• Grey goo- Earth is consumed by rouge nano machines turning matter into more of themselves
• Aliens create in-only forcefield around earth, allowing no heat to escape and dooming us to a very hot grave

Fantasy:

• Angry wizards cause mass-scale global warming
• Angry wizards craft memetic mental virus
• Angry wizards create self-casting spell that sucks lifeforce out of the entire earth
• Angry wizards do anything really
• Incompetent pointy-haired hero accidentally destroys one of the four elemental orbs
• Demon-lord wins after all
• Gods get fed up with the world's shit
• Death note uploaded to digital format

General:

• Earth launched into sun
• Heat death of the universe (All energy is eventually converted into heat, and cannot be changed back)

Fantasy:
Unleashed ancient magic consumes our sanity

Gods say fuck it and leaves, all nature just dies.

Sci-Fi:

Aquatic alients forces the polar icecaps to melt and drags our civilzation under water.

Alien race covers our planet in vulcanic ashes, suffocating all life.

hmm.. this really is split into two additional categories beyond fantasy / Sci-fi.
- Physically destroy the world, leaving something like an Alderaan-style asteroid belt behind (or even nothing at all)
- Make the world uninhabitable for humanity as it is now. Lots of ways to do that.

The latter is relatively easy. The former much harder, requiring far more energy.

Von Neumann architecture is one of the easier ways to accomplish the latter. Machines using any raw materials to make more of themselves designed to do the same. Eventually such would result in the world being such machines, nothing else. If machines are small, it would be nanite goo.

I've been thinking about time travel a lot recently, and I figure that if any two governments in the world got hold of time travel technology, they could easily use it to create a very interesting World War 3+. I started a project a few days back (Heavily inspired by the RTS Achron) in which two factions (A Government and a rebel faction) create a secondary universe from which they communicate with their agents on earth, changing the timeline from the invention of time control onward at will. The Government has a huge numbers advantage both in the secondary and primary universe, but due to some beautifully executed plans the rebels have more experience and skill with chronological strategy.

Basically the world will end in thousands of ways during the time war, from nukes to viruses to paradoxes. All because of the invention of time travel and a few people who weren't content with one nation having such a large advantage in both politics and war.

There's a really good post-apocalyptic table top rpg called Eclipse Phase. The apocolypse there was caused by rogue seed AI (basically a computer that can learn, evolve and make more computers like itself) called the TITANs they pretty much destroyed earth beyond repair, then went after humans living on Luna and Mars, and just when everyone thought humanity would be wiped out the TITANs disappeared without a trace. There are remnants of them left occupying earth, but the TITANs themselves are gone somewhere else.