Introduction: K'nex Crossbow

To create this diabolical monstrosity, you will need:

25 yellow connectors
6 red connectors
32 small green rods
1 blue rod
15 white rods
1 gray rod
3 yellow rods
1+ rubber band
1 orange connector
2 white connectors
10 gray horseshoe connectors

Step 1: Main Frame

The frame is made of 7 of these three-connector units.

Step 2: Handle/Grip

Step 3: The Cross of the Bow

First take the last unit of the frame and attach a yellow rod to the middle connector.  Then add the white snowflake connectors on either end, after which you can put on the two other yellow rods.  Wrapping the rubber band(s) around the cross is pretty simple.

Step 4: Firing

You will need the bolt (top) and pin.  The bolt slides perfectly into the channel, and the pin locks it in place.  Then draw the rubber band to the red connector.  Yank the pin to fire.