DS1 gets a book to read and write a review on every wednesday, if he doesn't do it by the following week, he just keeps it until it's done.
He gets spellings each week which he also has to write sentences with.
Friday night he brings home a worksheet, usually maths, do do over the weekend and occasionally he has greek homework to do as well.
We do our best to get it done around everything else, but DS is doing well at school so I figure if it doesn't get done, it doesn't get done. He does it all about 95% of the time.