This is a fun way to talk about 3D shapes. All you need are toothpicks and miniatures marshmallows! Brayden did this in his Kindergarten class this year.
Give your child some toothpicks and marshmallows. I suggest you sit and do this activity with your child while he works on it. Then let your imaginations run while you build fun 3D creations! Talk about the names of the shapes you create (like a cube).
I would say this is for children 3 and up. Some more mature two year olds could do it, so long as they have the fine motor control to not poke themselves and to also create these items without getting frustrated in the process.