I thought this might be fun for some people (though not to everyones tastes to be sure). This is a famous example (I've altered it into what I believe is the strongest version).

You need to accept the cases as written - if you alter the cases the solution is easy. The problem is coming to a solution ON THE ASSUMPTION that the cases are precisely as described.

CASE ONE

You are on a train. You have the controls for the train (and there isn't anybody else around). Up ahead on the tracks you can see 6 living people who are tied to the track. If you do nothing then those 6 people will be mowed by the train and they will die. You are able to press a lever to divert the train onto a left track before it hits the 6 people, though. You are unable to stop the train (or do anything else) because the brake is broken. There is 1 person tied to the left track and that person will die if you divert the train.

Should you:
A: Do nothing (1 person will live and 6 will die)
B: Do something (6 people will live and 1 will die)

CASE TWO

You are a surgeon on an isolated island. You are a (somewhat surprisingly) specialist surgeon who is very proficient in all kinds of organ transplants. You have precisely 7 patients under your care. 1 person needs you to operate on him. If you operate on the 1 person you can save his life. If you don't operate on him he will die. If he dies then you can harvest his organs to save your 6 other patients. If you do operate on him and save his life your 6 patients will die because they won't receive the organs they need.

Should you:
A: Do something (1 person will live and 6 will die)
B: Do nothing (6 people will live and 1 will die)

The problem is that the reason people give to justify their answer in the first case typically prescribes (on the grounds of consistency) that they answer in a way they find abhorrent in the second case. The cases (or variations on them) have generated quite a literature... What do people think?