Children love marbles: their colors, their smooth texture, and how they move, roll, and spin. Playing with rolling marbles also offers opportunities for children to learn about motion, and the different things that affect it.
If you have some marbles, give them to your child in a shoebox, or other smooth-bottomed container. Give your child plenty of time to look at them, feel them, and just roll them around inside the box.
If your child maintains an interest, try making some marble ramps using pieces of cardboard and masking tape. By folding the cardboard lengthwise you can make some ramps that the marble will stay on. Invite your child to put the ramps together (with your help if needed) in any way she wants to. Then watch as the marble goes down one ramp and up the other.
Can it make it all the way to the top? How can you change the ramp so it will go all the way up? Remember to supervise very young children with marbles, as they may be tempted to put them in their mouths!