The first thing you need is a bunch of playcards
Take two of them out of the stock.
Set them against each other.
Magic! If you do it right they will stand by them selfes now.
Do the same thing again. Be careful!
Set one card at the top of them. This is the base.
Do the two steps before again and again. You must be careful. They falls easily. When you have like four or three towers stending up you can start with the next floor.
Do it again and again. And you're done!