This is a simple and cheap dart to build that requires a few household items:
A bendy straw
Tape (Scotch tape recommended)
Toothpicks (4-5, depending on thickness of toothpicks)
This dart can either be thrown or used as a bolt with my K'nex Bolt Launcher.
Step 1: Preparing the Straw
Take the bendy straw and cut off the bendy part.
For those of you who have built my K'nex Bolt Launcher Bolt, this step should look very familiar.
Step 2: Adding the Tip
Take 3-4 toothpicks, depending on the thickness of them, your finger dexterity, your laziness, and how long you can go without becoming really frustrated, and shove them into one side of the straw.
When you have them in the straw, tape it to secure it to the straw. I did not tape the toothpicks in my picture because I used 4 toothpicks and they secured themselves in place.
Lastly, carefully place the last toothpick in the middle of the others in the straw. tape this one down carefully as this is the hardest part. Try to get the toothpick in so that it doesn't wobble too much when you push it a little bit.
I am really sorry that these pictures are really blurry. Read the notes and hopefully they clarify a few things.
Step 3: Throwing
If you are reading this, then you must either have no clue what a dart is, or you are just an idiot (Though if you are the former, then it is implied that you are the latter as well.).
To tell you the truth, how you throw this dart does not really make much of a difference because the front heavy dart will always fly straight (Not 100% guaranteed). Throw the dart however you want to, as long as you aren't aiming at something that could get you in trouble if you hit it (Example: me).
Happy dart throwing!