Some of the activities that we've used at the preschool where I work build fine motor in a fun way.
Place a coat hanger at the childs' level. Place different clothespins in a basket for the child to use at their leisure. We had different colors that children would often pattern without prompt. You could also put different numbers or letters. We would also use tweezers and place them next to an old sunflower so that children could take out the seeds.
Another activity that is challenging for children just learning this skill is to place different colored water in plastic egg cartons or ice cube trays. Using eyedroppers the children can take color from one and mix with another color.