This is a One-Off Question Of The
Day because I found a question that I thought would make a good
Question Of The Day.

A prince is sent to jail and locked
up in a tower. The guard takes pity on his and gives him a chance
to escape being hanged

The guard gives the prince two
boxes. One contains 50 blue marbes and the other contains 50 red
marbles. He will wear a blindfold and pick a marble out. If it is
blue, he'll help the prince escape. If it is red, the prince will
be hanged. The guard tells the prince that he can rearrange the
marbles any way he likes, but he has to use all the marbles.

After a night of rearranging the
marbles, he manages to increase his chances of surviving to
almost 75%. How did he do it?