Free capacitative stylus: old pen, sponge, and a paper clip. It really works, though the sponge part has to stay somewhat moist.

Instructions: 

1. Remove the ink parts and guts from a pen (you may need to snip off the end to make the hole bigger).
2. Poke a small hole near the writing end of the pen—just enough to fit a paper clip in.
3. Stuff a moist sponge where the nub was (you’ll probably want to push it in from the inside).
4. Insert one end of an unwound paper clip into the hole, making sure the end of it is inserted into the sponge.
5. Wrap the rest around the pen so your fingers will touch it when you use it.
6. See photo—it basically shows what you need to do.
7. Remember, the sponge must stay slightly moist.
8. Also remember, this project is more fun than useful.

Bonus facts:

• You can use an all-metal pen instead, just write upside down.
• Wrap a pencil in aluminum foil. Ta-da!
• Or just use a binder clip. Seriously.

That said, all of this information is essentially useless since you can buy a 4-pack of actual styli for $1 on Amazon. But it’s fun to hack shit, right?