Learn how to make a crossbow out of easily available household/office items- not least of which, a ruler! Why only use a ruler to measure stuff? Turn it into a weapon instead!

Step 1: Materials

The things you'll need:

A Ruler (steel, wooden or plastic- I happened to have steel)

Two unsharpened pencils (or something of equal length like disposable chopsticks)

Rubber Bands (amount depends on how tense you want the bow)

Strong Tape (I used 3M brand clear duct tape- strong glue may work too)

A drinking straw

Medium sized Binder Clip (wide enough to fit over the end of the ruler)

3M Wall Hook things (as a handle/grip)

Bamboo (Shish Kebab) Skewers (for arrows)

Step 2: Construction of Bow

Step 1: Tape the two pencils together. Make sure you leave either end of the pencils
               untaped so you can can get the rubber bands between the pencils later

Step 2: Tape the two pencils to the top of the ruler so they are perpendicular to each
              other- like a cross without the top.

Step 3: Rubber Bands

Step 3: I used four rubber bands, but looking back I probably could've done it with two
and gotten more power. Anyway knot the bands together as shown in the
picture below.

Step 4: Attaching the Rubber Bands

Step 4: Slide one of the double over bands between the two pencils at one and tape in
place. Do the same with the other end.

Step 5: Final Touches

Step 5: Cut a small length of the drinking straw. (not too long or the bands will catch on
              the straw and therefore decrease the amount of power. Tape the straw piece to
              the ruler near where the tip of you arrow will rest when loaded.

Step 6: Take the 3M Wall Hook thing and attach it to the underside of the ruler (hook
              end facing you) to use as a handle/grip.

Step 7: Put the binder clip on the end of the ruler. If your ruler is steel/metal. the clip
              may slide around easily. Just add a piece of tape the part of the ruler where the
              clip grips.

Step 6: Load and Fire Away!

All Done! You're ready to fire away! Don't fire at anyone though. You could skewer someone's eye.

Notes on loading. It may help to wrap a bit of tape around the middle of the bands to
                                 aid placement behind the arrow.

   Load the bands first. Pull the bands down and into the clip. Then
                               insert the skewer arrow through the straw and push into the binder
                                 clip.

                                  Fire by simply squeezing the binder clip ends.