OK, I'm going to stop after this gets explained to me:

Four Men Crossing a Bridge (from Microsoft interview process)
There are four men who would all like to cross a rickety old bridge. (Perhaps it is more accurate to say that they'd like to get to the other side.) The old bridge will only support 2 men at a time, and it is night time, so every crossing must use the one flashlight that they all share. The four men each have different walking speeds; the fastest each of them can cross is 1 minute, 2 minutes, 5 minutes, and 10 minutes. If they pair up, since they must share the flashlight, they can only cross in the time that it would take the slower of the two. Given that the shortest time to get them all across is 17 minutes total, how should they all cross?

I can't come up with less than 19 mn - how do they get 17 mn?