You will need: sweets (marshmallows or gumdrops/fruit pastels work well), cocktail sticks (garden sticks would do if the ends are pointy enough to work).
We set a timer and made as many 2d shapes as we could. Then, we put some 3D shapes into the table and tried to make those. Finally, we made anything we wanted. My children made a bridge for their animal figures and a very complicated 3D shape.
Mostly though, it was a lot of fun (and a great way to eat some sweets afterwards!)