Okay, so I've never actually seen anyone keep a Robot Lab Book, but this link will take you to a checklist that describes how and what goes into a Lab Book (Chemistry). With some slight modifications, this list could easily describe for a robot club, FLL team, or other organization a way to help kids organize their experiments with the NXT kit.
I remember keeping Chemistry and Physics lab books in college, and the rules were fairly strict and part of our grade was based on a review of our book(s) at the end of semesters. No pencil, of course - everything was in ink. A torn out page could get you an automatic letter grade loss, no kidding.
Still, it's an interesting article and maybe someone can come up with a version of the checklist for teachers/coaches.