Karen wants Jack to be safe. Safe from the enemies of childhood honesty, safe from the indignities of being the oddball, and safe, she hopes, from ever really having to face all that he will never be or have. The fun and the absurdity begin right there. Ten years olds, no matter how old they look, are all alike. Body noises are reasons to giggle.
Girls are the enemy.
And Penthouse becomes an obsession. Robin Williams does a masterful job of portraying the average ten year old. He is shy and courageous within nanoseconds of each other. His teacher becomes his love interest. And when the guys beckon, Jack has all the resolve of a wet noodle.