For this fun bet you'll need about 20 cards.
Turn five of the cards face up and then mix then in with the face down cards.
So you'll end up with a packet that has five face up cards in it.
Have your friend shuffle the cards as much as they want and then say that you can place
the cards behind your back, and within 15 seconds, sort them into 2 groups, and that
each of the groups will have the same number of face up cards.
It sounds impossible but it is this simple.
Now there are one, two, three, face up cards in this group, and one, two, three face up
cards here.
You've won the bet.
The solution is simple.
When you place the cards behind your back simply count off the top five cards and turn
them over.
That way, the packet of cards in your left hand will the same number of face up cards
as the packet of cards in your right hand.
It's amazing and it will work every time.