Renweb

Renweb is very helpful if you want to know what your grades are but it's also very helpful in many other ways.
You can check your homework on it. So, in case you don't remember what you had to do because you left your assignment book at school, you can just look on there and see what you have to do.
I hardly ever check mine, unless I think I might have a low grade in a class. I'll start using it to make sure I got all my homework now. I should probably start checking my grades more often too, to know if I forgot to turn an assignment in, or something like that.