You are at a party with a friend and 10 people are present including you and the friend. Your friend makes you a wager that for every person you find that has the same birthday as you, you get $1; for every person he finds that does not have the same birthday as you, he gets $2. Would you accept the wager?

There is a 1/365 chance that you share the same birthday with a random person, and 364/365 chance you don't. Don't take the wager.