* "Road to Europe" (Season 11, Episode 15): This is where Peter initially gets the tank, winning it at a carnival. He then takes it on a wild road trip to Europe.
* "The High School Reunion" (Season 12, Episode 10): The tank is featured in this episode when Peter gets into a fight with a rival from his high school reunion.
So, while it's not just one episode, those two episodes highlight Peter's tank-owning adventures.