My favorite trick for math curriculum users who have bored children - at the start of a new chapter/section give them 24 hours to review the material and then give them the "test".
If they do 90% or better they know the material and they don't need to do that section. If they don't get a 90% or better - they have to cover the material in that section as you normally would have assigned it.
This method gives them a ton of motivation to do their very best work on the test, prevents them from having to repeat a bunch of stuff they already know, and helps them quickly move up to a level of math where they are actually able to learn something without you worrying they are missing something.
