My son is 13 and grounded for bad grades I need ideas of thing's for him to do?

He is grounded for 1 month cause he is failing 4 cles in 7th grade. Not turning in ignments and not even bringing homework home. I need ideas of thing's to keep him busy that will help him with this issue. He will be going to an after school program tue wed & thurs to help him with his homework. So no video games, or t.v, & I would like him to be doing something constructive rather than house work like his dad suggested. Any ideas would be helpful! Thanks in advance :)