PUZZLEBOXX

First - fold the card in half lengthways and cut as shown below (red lines)

Now unfold the card and cut as shown below (red line)

With care, open out the card (to a kind of jagged circle).

This should be large enough to pass a football through!

If you are very careful, it is possible to cut the card so that you can step through the hole!  (This does need some practice ... and a lot of care!)