National Council of Teachers of Mathematics
Nctm: Standards for School Mathematics
This standards-based NCTM website offers resources for teachers of mathematics for all grade levels, including interactive math tools, lesson plans, online resources, and the like.
Other
Exemplars: Thermometer Rubric
This rubric is appropriate to use with older students. It features a way for students to self-assess by drawing a line on the thermometer. Teachers could also assess using the same thermometer rubric.
Other
Pare: Designing Scoring Rubrics for Your Classroom
What do you know about designing scoring rubrics for your classroom? This site features an article that details how and when to use rubrics in the assessment process. It also gives examples of rubrics used in classrooms.