I noticed the Toy contest and thought that was a good enough excuse to do something Nintendo related. After a bit of though this is what I've come up with. I hope you like it :)

Before anyone asks:

Yes I drew all of the parts and graphics up myself (using Adobe Illustrator)
And yes I am aware that it might not be 100 percent accurate to the Mario design (if anyone is that geeky hehe)

Start off by downloading the PDF and printing everything off. Use around 180gsm card for this. (if you don't make sure you have some cereal box card handy and stick the background to that, everything else should work OK in paper)

mario knock em down instructable.pdf
Download

Step 1: The Mushrooms and Blocks

You have got a lot of cutting and scoring to do so get going. As you can see make sure you crease all of the folds (indicated by dotted lines) really well.

I used a scalpel and a glue gun to cut and assemble the parts as I found this the easiest. You can use PVA etc however you will need to take your time and hold it in place until it sticks.

Glue the faces mark "A" to each other to make the mushroom. Do not glue the mushroom to the block or else it will never get knocked off ;)

Step 2: The Ammo

Make sure you crease the Ammo really well as it is a little fiddly.

Start by gluing the two sides together then bring them together as shown in the photos.

The Ammo caddy is simply one glue tab and should end up looking like what you see in the photo

Step 3: The Background

When you have the background and stands all cut and creased, ensure the slots (see photo) are cut well. Do not just make a slit or else you may have difficulty assembling it.

Glue the stands into place by slotting them into the background and gluing in place as shown.

Step 4: Final Assembly and Play Time

Glue the blocks to the background (match up the faces labelled "B" on the boxes to the background markings labelled "B").

Now simply position you background on a desk, set up your mushrooms and flick away.

See who needs the least amount of go's to knock off all three mushrooms.

Hope you enjoyed this instructable