you know, it might not be a bad idea to hold onto those things and pass them down to Little Steve Dave some day
First make him take up the hobby. If he doesn't care for it, just push harder. Don't be afraid to smack him in his face and call him names to get it done. He'll thank you for it later on down the road. It's a financial investment and a pastime. Sometimes the best thing for your kid is a bloody nose and a pack of baseball cards. 
violence? no. i'm sorry but we're going to have to agree to disagree on this one.
the best way to get him to like collecting ken griffey jr baseball cards is to continue to super glue a different KGJ card to the kid every day until he starts liking them. start with his chest, then his back, arms, forehead, etc. glue the entire card to him too, you may consider using a paint brush, dipping it into a can of super glue, and brushing the adhesive onto the card so that it sticks really well.
anyway, that's how i would do it and i bet it would work rather well.
