I am working together with my sister to teach our boys some things over the summer. (brace yourself, both these kids are way behind what’s common here lol )
But the cousins are at different levels, and the younger one (mine) is further along. The older is going in to public k next year. My son is 4 already but his birthday is in December and he isn’t starting K at his school (Montessori) for another year.
My son can read CVC words, some sight words, and some blends. (no early, early learning with him, I just didn’t know). When she asked me if we wanted to do “phonics” with them over the summer (as well as writing and some math), I was excited because I just know it will be much more fun with both of them together. But then, when I asked her what phonics things she was thinking of, she said "letter recognition, letter sounds, and for numbers…the numbers 6 and 7). I figured for math we can just do games that go to 100, which my son is not proficient at yet. 6 and 7 are in there. 
But with phonics/reading, I’m trying to find some games both can do where both are growing. Any ideas? I’m hoping to find/create some active games, since both are active boys. (who get more active when together)
I thought a frisbee letter/phonogram hunt would be fun. Spread out frisbees with letters and phonograms on them. They can hunt for the one they need (give a letter to my nephew and a phonogram to my son, but have all the frisbees mixed up). They find it and throw it back.
I’ve got a few more ideas like this, but need more.
(this will be just an hour or two in the afternoon, I plan to do a more intense reading program and jones geniuses math matrix with him in the morning without his cousin)
Also, any math games for number recognition to 100, or skip counting would be appreciated.