Shape poems are an effective tool to encourage third-grade students to appreciate and understand poetry. Have each student choose a shape she would like to write about. It can be the shape of something known, like trees, flowers, fruit or pets, or a completely unusual and creative shape. Next, have students make a list of words to describe the shape, being sure they include plenty of words. Then have students use the words they've listed to make an outline of the shape. The words actually serve as the lines for the drawing. Another twist to this project is to have students write one word over and over again, forming it into the shape of the object they are naming -- for example, using the repeated word "triangle" to form the lines of a triangle.
Third-grade students have things they feel strongly about, so giving them the opportunity to write letters to senators, congressmen, local government officials and others gives them the chance to express themselves while learning letter writing. Introduce the lesson by showing examples of letters from famous people they might recognize or other letters. Have students work in groups to discuss an issue they feel strongly about and bring their ideas to the rest of the classroom. Have the class vote on one issue they want to write about, then ask each student to compose his own letter to the official. Send the letters together in one large envelope. Most likely the class will receive a letter from the government official addressing their concerns and thanking them for being involved. Compare this letter to the letters they wrote and review the components of good letter writing.
Journal writing is an effective way of encouraging creativity in writing for third graders. Use journal writing once a week and have students write from a prompt you give them. For this exercise, use an amount of time rather than a set number of lines or pages. This way the students can write as much as they can during the time period and not feel constrained or inhibited by having to produce a certain amount. On a few journal writing days, make it a free write, where students can write about whatever is on their minds at the time. Make sure students understand they don't have to show their journal writing to anyone but the teacher unless they choose to.
Third-grade students often do a unit on fables. Use this opportunity to get your third-grade students writing their own fables. Discuss the parts of a fable and read together some famous fables before students start on their own. Encourage them not just to rewrite famous fables but to come up with their own original ideas. Have students illustrate their fables and put together a classroom book of fables. Make copies and bind them so each student can have one at the end of the unit.