Look for a science program afterschool for him. My son goes to one at our school but they also do them at libraries, community centers etc. You may have one and not know it. Also check with your local science museum, zoo or anything like that and ask them!
If he likes to play video games, look for Spelling Challenges for DS or any other computer games. My DS just did a mid-year skip into 2nd and he loves Oregon Trail, Nancy Drew Mysteries (good for logic) a DK CD called I Love Science, Zoombinis and a bunch of other good educational games.
