There isn't a kid (or adult) that doesn't love the chance to just bang away as fast they can pull the trigger on a 10/22. The advantage of the 10/22 is there are so many different ways to upgrade, modify, tweak, and otherwise grow that it's an extremely versatile first platform. The added benefit is, you can teach them restraint. The faster you pull the trigger, the worse your accuracy, and the sooner we head home.
If not that, then a Henry lever action
If not that, then a Henry lever action