http://www.schooltube.com/video/b06bd6006c2b4ea8a2a0/Area-and-Perimeter-of-Irregular-Shapes
-Good video if a student missed a class or needed some review to do homework. Simple, but gets the point across.

http://www.schooltube.com/video/d94447e437264fc74e14/Triangle-Song
-Goofy video about triangle. My students would roll their eyes and say it's stupid, but it would help them remember it for sure.

http://www.schooltube.com/video/fd1644eb7e1fe542df25/Solving-Systems-of-Equations-by-Elimination
-Another really clear review video, a little quick, but would be good if a student had already seen the lesson once.