Recently my class spent some time reviewing apps for Android devices as a seque into learning about App Inventor (formerly hosted by Google, now by MIT) and building their own apps. The class created an evaluation matrix in Google Docs using color codes for "thumbs up" and "thumbs down" apps. Each student had to nominate an app on the list and then evaluate the ones others nominated. You can tell which app a student nominated because the cell at the intersection of the app and the student is white and includes their justification for niminating it. Its pretty interesting to zoom out and see the consensus achieved on some apps by students and how that can differ from the instructor (my!) evaluations.