With all the paper crafts I've been into lately, making my own paper was only a matter of time.
The process: Tear up old paper, fill a plastic Tupperware bowl, boil water in your trusty water boiling device (sometimes referred to as a tea kettle), add some of that hot water to the paper filled Tupperware, and stir a little (just for the fun of it). Leave the room and eat some cookies, while waiting for the paper to soak. When your patience runs out (mine ran out after 20 minutes or so), take your trusty squishy stuff maker, or as I like to call it - The Stick.
I suppose you can use a normal blender too, but hand blenders are more fun and easier to clean.
Stick The Stick into the Tupperware paper mixture and blend until it gets all squishy and you can never tell in a million years that it used to be torn up paper. You want something like a thicker milkshake consistency. Add some cornstarch and blend some more.
Take a towel and place it on a flat surface, with a plastic bag, or something waterproof under it. Take a tea towel and place it on the towel towel. Using a spoon spread your paper paste on the tea towel, trying to get an even layer. The thicker your layer of paste, the thicker your paper will be. I applied mine pretty thick, because a) I had no idea what I was doing and b) I had no idea what I was doing. Level the layer a bit, and cover it with another tea towel. Place yet another towel towel on top of it, and pat with your hands, place a heavy book on top of it, or use a kitchen roller to absorb the water. Heavy book or roller are a must anyway, because you want you paper to be flat. Remove the top towels and leave to dry. This is going to take forever.
Options to speed up drying: blow dryer, ironing it, or placing it on a heater (which is what I did, and got curled and wavy paper).
The end result is pictured below. Its thickness is somewhere between a postcard and a cereal box. And I have absolutely no idea what I'm going to use it for.