This little gem of a converstation I heard while both of them were flexing in the bathroom after their shower:

Isaac: wow, penn, I can tell your muscles are getting bigger every day...

Penn: Oh yeah...maybe i'm a giant

Isaac: no, Penn your not a giant, Dad is like a giant, but Smiths are just really strong guys.

Penn: yep!

Isaac: check out my kettle bell muscles- can you see them?

penn: uh, can't you see my muscles too!