In the episode where Bobby is afraid of heights, the Brady's decide to buy a trampoline. As Bobby sits up in his room looking out the window at his family jumping on the trampoline, the camera shows a closer view of the family on the trampoline. As Peter gets on and starts jumping, the family starts cheering and clapping. Mrs. Brady accidentally says, "Go get 'em, Chris!" or something along the lines of that phrase as she's cheering. Chris being "Peter's" real name.