Asteroids. Big lumps of rock and metal floating in the endless void of space. The Dawn probe is about to enter orbit around Vesta, where it will stay a year before moving on to Ceres.

So I was wondering: What can you actually do with Asteroids? They seem pretty useless, but here are some ideas:

1. Prisons: Try to escape from a ball of rock a few hundred kilometers in diameter, literally out in the middle of no-where. Good luck.
2. Mining: Some asteroids contain valuable metals or minerals or even tiny primordial black holes, and could be a source of conflict if more than one party claims them.
3. Warfare: Use them as a military base or crash them into a planet. It ensured victory over the dinosaurs.
4. Secret hideout: Pirates, spies, alien invaders, mad scientists, religious fanatics, the Space Mafia, rich eccentrics, anybody who wishes to remain out of the limelight for a while may set up shop on an asteroid.
5. Space ship: Hollow them out, put in quarters and a big drive system, and ride a chunk of rock to the stars. In theory you could even use the rock of the asteroid itself as reaction mass.
6. Waystation: Use it as a refueling and resupplying depot on your way to the outer system, or assemble your first FTL ship using that asteroid as a base.
7. Monuments: What better place for the grave of your early space heroes than an asteroid cemetary?
8. Natural Hazard: Very dense asteroid belts might actually pose a hazard to spaceships. The asteroid belt in the Solar System doesn’t; but it’s a staple of Space Operae to posit belts where asteroid tumble about chaotically and close enough to each other to constantly bump into one another. If a belt is created within the story’s timeframe, say by destroying a planet, it could become a new hazard to hyperspace lanes or what have you.
9. Doomsday: In fiction, asteroids have a habit of constantly crashing into Earth or other inhabited planets. The players could either be helpless to stop it, and need to deal with a society gone wild in expectation of doomsday, or are heroic heroes that get sent into space to help Bruce Willis blow up that approaching menace.
10. Mystery: Back in the days, people thought the asteroids might be the left-over of a fifth planet that was ripped apart. They don’t have enough mass, among other things, so this seems no longer plausible. That doesn’t mean it isn’t true in your fictional universe – and it might be the origin of asteroid belts in other systems. The players could hunt for artifacts from the fifth planet, prevent a similar fate from befalling Earth, could encounter Aliens in cold sleep, survivors from the catastrophe; or they could travel back in time to prevent the disaster (or, in a twist, cause the disaster in the first place to keep the timeline intact).

What other uses could asteroids have in adventures? How have you used asteroids in your games or stories?