We had fun making and playing with this the other day, it is easy enough to do and would make a great snow/rainy day craft. you don't need a massive piece of card to make it, a big box would work fine.
What you need:
large piece of card
2 milk cartons
small card box for the goal
double sided sticky tape
Cut your milk carton in half, length ways, and then half again to you have 2 corner pieces.
Staple the open end
About 5cm from the stapled end cut out a v shape, it needs to be big enough to fit the marble through.
Repeat for all the other milk carton pieces.
Lay the milk carton pieces onto the large piece of card, it is a good idea to work out where they should go before you stick them down. Once you are happy with the layout, stick the milk carton pieces in place with double sided sticky tape. Use the small box to make a goal, we used some card to make 3 sections and then added scores. Stick to the big piece of card, the get your marble and see if you can get it in the goal ,it is actually a lot harder than it looks!