I just overheard Carter ask this question to Steve:

 Dad, Why haven't we ever gone to Pluto?  

Steve was just as speechless as I was, but came up with "ball of ice"  "too far"  "no life", etc.

And Carter corrected him and said,

No Dad, it's because we didn't PLAN IT!

Ah ha..ah ha  ha!

Then he chimed in with this:

Knock Knock

  Who's There

Abraham Lincoln

Abraham Lincoln Who?

Seriously??  You don't know who Abraham Lincoln is?