This is a crossbow made entirely of megablox. Depending on the age of your megablox, the pieces may not hold together as well. So this is only for decoration, not to pick up and mess around with. I will use a specific number of blocks in this instructable, but you can shorten it for better durability if you wish.
Step 1: Stock
First make a stack of 11 4x2 bricks. Then, add three more 4x2s of a different colour (I used red). On the butt end use two blue 4x2s so that a single row of 4 sticks out from the top and bottom.
Step 2: Holder #1
This is the first holder for the bow of the crossbow. First add two red 2x2s tothe three reds (as shown). Then add one curved 2 blue (the trigger) in the middle (as shown) leaving one stud on either side of it. Put two 4x2 blues on top of this. Then duplicate the 4x2 reds and add two curved 2 yellows on the other side (the trigger gaurd). These will help you tell which part of the stock you put down.
Step 3: Holder #2
Put four more 4x2 reds on top of holder #1. Then add four 2x2 yellows on the top red so that half of them stick out (as shown). Put two blue 4x2s on top of this. Finally, us two blue 4x2s on top (as shown) so that half of each stick out. Now your stock has been completed.
Step 4: Bow Handle
The easiest part. Use four red 2x2s and put one yellow 2x2 on top.
Step 5: Curve of the Bow
On top of the handle add eight 2x2 reds diagonally ( as shown). Make sure the bottom one is attached to the handle only halfway. Then add another two greens to it ( see the picture). For the bottom, first add one 2x2 green the normal way to the bottom of the handle. Then add nine more green 2x2s diagonally. Ignore the extra yellow I have at the bottom. Now give yourself a pat on the back, the string is simple but is the most annoying part of the crossbow.
Step 6: The String
First make a stack of for yellows (2x2) . Then add two reds. Then six greens. A yellow. Seven more greens. And finally, three yellows. Add a yellow to the top and bottom as shown in the picture.
Step 7: Stringing the Bow
Take the string and attach the two open studs on the top and bottom to their respective green 2x2s ( As shown in the picture).
Step 8: The Bolt
The fletchings will be two curved 2 yellows. The stick will be four 2x2 yellows. The head will be two 4x2 blues, two curved 2 yellows, and finally a single stud baby MegaBlock. (If you do not have one just use a red 2x2)
Step 9: Bowing the Crossbow
This easy. Put in the bow so that it fits in the slots. This is also really annoying if your megablox are old or worn (like mine). Then the string will sag or break. If this happens shorten the space between holder 1 and 2. then decrease the length of the curve and string. If you do not want to do this, put a block under the two ends of the bow.
Step 10: The Finished Crossbow
Put the bolt on top so it goes between the string and handle. Voila! You have a MegaBlox Crossbow! It looks mildly or or intermediately impressive depending on the colours used. You usually will get a 'cool' or 'how do you think of that' from guests.