Start by cutting the hole in the tissue box a bit larger so that everyone in the family has a fair chance of shooting the rubber bands in. Then stand the box upon a table.
--STEP 2--
Place masking tape/a stick/long ruler/ribbon (or anything else that has a straight line) a bit of a distance from the tissue box and stand behind it. Adjust the distance according to age.
--STEP 3--
Have the rubber bands ready by your side and give everyone just one minute to see how many they can shoot into the box.
The one with the most rubber bands on target wins!