This is a great tool to use to have your students grade their peers on a group project.
Students have 10 points (or you can choose a different point value) to distribute to their peers. Students then have to explain why they gave the grade they did to each of their group members. The teacher then adds all of the points given to each student.
All grades are kept private between the student and the teacher, no student knows who gave who what grade.
Peer evaluations can be formally used as part of a students grade or informally to help a teacher better see a students perspective of how s/he feels a peer is contributing during group work.