This blog entry from "Math Workshop Adventures" has a lot of information about how the teachers approached Common Core standards related to fractions in third grade. The anchor charts are a great visual that you can create with your students 'on the carpet.'
Ohio's Online Resource Center has a very good collection of inquiry-oriented, open-ended math questions that you can choose based upon grade level and topic! The range is from third grade to high school, so finding a quality question that meets your students' needs is easy!