One fun activity for students who are learning to use a ruler is to have them measure different parts of themselves. Create a worksheet that lists several different body parts for students to measure such as, feet, hands, fingers and toes. For homework, they will measure the different parts with the help of a parent if they need it, and write the answers down to share with the class. You can also have them measure an adult's feet, hands and so on to compare to their own.
Prepare a list of measurements that the students must find within the classroom. Divide the children into groups of two so they can work together to find the items. The different measurements should be small, under one foot, so that the students can find and measure them easily. It is a good idea to find the items first. Give the students clues that pertain to the specific item that you want them to find. For example, "I am seven inches long and I hold things together." This would be a clue for a stapler that is on your desk. Give everyone a small prize, such as a piece of candy, for correctly finishing the hunt.
Have students complete an activity in which they make and design their own ruler. Cut out strips of paper before the activity that are the size and shape of a typical foot-long ruler. These strips can be different colors or plain white. Students will use a ruler to make the inch and centimeter marks on their paper, then design and decorate it any way that they want to. If you have access to one, use the laminating machine after class. This will preserve the rulers so that the students can use them for the remainder of the school year.
Give students a large piece of construction paper to use as the base for their project. Create a list of directions for the students to follow that include specific shapes and sizes. For example, a triangle that has sides that are 3 inches in length, a square that has sides measuring 2 inches and a circle with a diameter of 1 inch. The students can then choose what colors they want to make their shapes and where to place them on their paper. This activity may be more appropriate with slightly older elementary students, in fourth or fifth grade, because it deals with geometry concepts such as diameter.