Our 5-year-old son lives by a simple credo: Never, ever be bored! He’s always investigating, always testing, usually grubby, never still—not even in his sleep. Liam doesn’t share his father’s fear of heights or snakes, nor does he possess his mother’s good sense. His favorite phrase typically occurs too late for Mom, Dad, or older siblings to intervene. “Watch this!” he’ll announce as he begins his incautious leap to . . . wherever.