You can buy sets of pins or skittles like the ones in the picture above for a relatively low-cost at most bargain stores. Alternatively, use empty plastic bottles to make your own pins and a small ball you already have at home.
Hallways make great indoor bowling alleys. Set up your pins in a triangle shape, aim and bowl. If the bottles are knocked over too easily fill them with a little bit of water - just remember to put the lid back on tight. Smaller children can use a larger ball, while older children may find a tennis-sized ball more challenging. Younger children can also aim and bowl closer to the pins. How many can you knock over at once?