Take a sheet of paper. Make a rectangular tray out of it. Staple the inner sides so that it can contain water.
Add water to the paper tray slowly. Wet the outer sides of the tray lightly with your hands, where it will be touching the heat.
Place the paper tray on a fire source like stove or lighter. Keep the heat low so the outer surface of the paper cup gets time to absorb water from inside too. Make sure that the parts in contact with fire are wet or else your plan will be doomed.
The water will gain heat now and in about five minutes or so you will see it boiling. Invite onlookers to witness the scene or take pictures (if you are able with one hand). Now is your time as a magician or a scientist.
You can do the same by making a paper cup. make a cylindrical shaped cup with paper and wet the outer bottom. Place it on a lighter or stove and soon you will have a cup of hot water. Make tea or cappuccino perhaps?