Spanish students develop spontaneous speaking as they role play (pretend to be) one of four members of the family as they go through Parque Morelos, Tijuana, Mexico. Each family member talks about his/her reactions, feelings, etc. as he/she views each new part of the park or new activity. As family members, they interact (agree, disagree, question, argue, ask for explanations, etc...) with each other in real conversations.
My 102 college class talked for about three minutes per visual, especially when they really became the people in the picture such as an overprotective mom, a daring dad, etc.