The "Graduation Night" episodes. When the first season ended on the Fox version and the first 5th graders went into middle school, Jeff told them he was going to miss them SO much, then added "You can't leave me, you're going to middle school...oh no" with humor.
Nathan in Season 2 getting a skateboard with Tony Hawk autographing it right in front of him (Nathan saved Tony twice in the game).
One episode had a contestant "flunk out" on the first question of the game, ending up with nothing. The contestant's wife was sitting in the audience for moral support, so Jeff invited her on-stage to play the game and try to win some money for their family.