S.C.
I have two boys, so this is right up my alley! :-) You mentioned balls - you may get him a basketball hoop. Playskool (I think) makes the plastic one that grows with them. Even at age 1, as long as he is standing/walking, would be a good choice. They also make one that is for kids that aren't quite walking yet where they just put the ball in the basket and it makes noise and counts and cheers them on. It is a basketball/learning toy. Also along the sports side, they make a Tball type toy that when you hit the ball with a bat it it just swings around, it is called a Playskool Swing n Score.
Now, if you are "outside" type people, some kind of car he can sit in and push with his feet or even a battery powered car/truck. My boys started on them as soon as they could walk.
Good luck!