The process drama is a huge part of dramatic play. Developed in part by educational theatre guru Cecily O'Neill, it encourages students to take on new roles without having to perform in the traditional sense. A process drama is a bit like improvising a play as you go along, but there is no audience. Each child will take on a new role and the teacher will think up a scenario, which can be as light as having the children pretend to be animals and come up with solutions on how to find their food, or as heavy as the children pretending to be soldiers in a war. Usually the process drama will have the students decide various solutions to a problem. The teacher will think up a large story for the children to take part in and will take a role that will guide them through. Refer to http://www.becominghistorians.org/using-process-drama for more in depth information on the process drama.
Bring in pictures of different people you have found in magazines or on the Internet. Have children pair off and face one another. Have them take turns either talking to each other as if they were those characters or having one child interview his partner as he takes on that character, and then have them switch.
Throw a "ball" around the circle, but not a real ball, mind you---this one is imaginary. Let the students know that when the ball is thrown to them, they can make it as big or as small as they want, using their hands to show themselves stretching it or shrinking it. The ball must be caught the way the person before them threw it (for example, a heavy ball must be caught as though it were burdensome), but they must throw it in the same way they created the new ball.
Have the children put on a play for themselves. Encourage them to bring old clothes to class to use for creating their costumes. Have the students either write a script together or use a commonly known fairytale. Make sure all of the students have a significant role if they want to to so no one feels left out. Doing a play for yourselves is about creating dramatic confidence, not about the end product.
This is a commonly practiced technique among theatre educators. Create a scenario, such as a town meeting or a person coming to ask their friends for advice. Create a character for yourself as the leader and come in to the space in character. Ask the children for advice on your situation or the issues that have come up in the town meeting. If you want the children to assume the characters of reporters or your friends, address them as such and they will likely catch on quickly. Remember, this activity should end when you feel it has reached and end or you run out of time. Be careful not to choose a child's solution as the best one. The purpose is to get them to brainstorm and offer up different solutions to problems. Your character should "leave" without having made a decision.
Have the students experiment with "finding their center." Have them walk around the space and then tell them to lead with their hips, or nose or hands. Discuss what they felt and what kinds of characters they feel walk with their noses in front, with their hips in front or their hands in front. Experiment with different body parts leading the way.
These activities can be combined to create a larger dramatic play activity or an entire unit. Remember, you can use these activities to go as deep or as light as you like. For further reading, explore the book "The Drama Classroom: Action, Reflection, Transformation," by Dr. Philip Taylor, which is an excellent resource for process drama and teacher-in-role.