Sgt. Frog Episode 170: Fuyuki and Keroro, Inaccurately! The Seven Wonders / Pururu and Chiruyo, Secret Friends
Episode 170 of 358 of Sgt. Frog, aired July 21, 2007, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Fuyuki and Keroro go to investigate the seven mysteries of the school. And then Pururu decides to stay with a certain memo-taking member of the Journalism Club who thinks the aliens are a comedy troupe... Source: crunchyroll