We do Khan Academy as part of out curriculum. He likes it, but he needs something more fun in addition to that. Once he gets a skill mastered in Khan Academy he doesn't want to touch it b/c he is afraid of it going down.(There is a color system for levels of mastery and if you get something wrong it lowers your level. I tell him it is b/c Sal (Sal Khan) wants him to practice it when he gets something worng, but the idea of dropping a level upsets him. I don't want him to have to get soemthing wrong in order to get him more practice, if that makes sense.
We also have manipulatives where we can do a version of Hands on Equations kind of stuff, but he tends to make up his own games. I really want him to practice manipulating expressions and equations. He has issues getting the terms isolated efficiently, and knowing what to switch to what side, and he could use the practice.