Wow, nothing in 2 days?
Okay, I'll bump the thread with a few more:
16: For whatever reason the players become responsible for taking care of/entertaining/showing around the child of an alien diplomat. This works better with alien aliens (as opposed to rubber forehead aliens) with alien personalites otherwise it is much less interesting. This could be adorable if the alien in question is young and friendly or traumatic if the party has to deal with a violent adolescent who wants to assert his dominance over everything. Probably best as a non-combat encounter,
17:You wake up in the morning next to someone you don't recognize or remember (and you don't recall going out last night). She only speaks [insert ancient, dead language here]. This is going to be very, very hard to explain, and there are probably going to be problems with culture shock and a lack of documentation. You can't exactly deport somebody back in time.
18: Players must fight their way out of an asteroid being mined in planetary orbit before it collides violently with the ground. Unfortunately, there are only three shuttles.
19: Players must fight in a field of glass that was the remanant of an orbital bombardment form some ancient war.
20: You wake up floating in 0-gee inside a spaceplane with several other people you don't recognize. Your chrono says it's been a month, but you can't remember anything. The autopilot tells you that the shuttle is preparing to land.