Here's how to make a small house out of just paper and water.

[edit] Steps

Get a bunch of paper. A notebook might be good. Take a sheet of paper and put it in some water. Make sure you get it really wet.
Slowly take out some water while mashing up the paper. Eventually you should have a ball of wet paper that has the consistency of Play Dough. If you don't, add or take out some water so the paper can absorb it and break up even more.
Make the paper ball into a little line, sort of like a worm, once you get into a clay-like substance.
Lay it down on a plate or tray so you can make the small house and put it out in the sun later. Keep making little lines out of more wet paper. Eventually you should have about 3 lines that make a square that's missing one side, or at least a piece of a side.
Make more lines, and put them vertically on the corners of the "square".
After each corner has a line on it, start mixing more "Play Dough" and instead of making more lines, just make them into little blocks or flat blocks, these will be your walls. Put them on the vertical lines until you have a cube that's missing 2 faces (top and one of the sides)
Make the roof however you want, but be creative on this one.
Leave the house out to dry in the sun.

[edit] Tips

This is just an example of how to build a paper house. It's a very fun hobby and there's no way you can mess up because its how YOU want it.
You don't have to just use plain paper, if you don't want. Make it sort of tie dye with food coloring, or just buy colored paper.
Don't forget to give your house some people to live in.
If you want, you can make a mini tray and stick it to the bottom of your house (make sure the bottom of the house is wet so it'll stay stuck when it dries) and put fertilizer in it so you can grow plants in it.
Remember to be creative, and don't let it get TOO wet after it dries or it can fall apart.