A massive drop in quality with this episode.
Plot In A Paragraph: Rachel sees an engagement announcement for her former fiancée and her former best friend. Keen to spend more time with her, Ross asks Rachel to keep his monkey Marcel for a day, and she loses him. All the gang come to help and everyone starts looking for him, Rachel calls Animal Control over to help, but she doesn't know that Ross is not allowed to have an exotic monkey. The Animal Control employee is in fact a former schoolmate of Monica and Rachel, and boy does she hate them, so the race is on to find the monkey first.
Jennifer Aniston looks cute in this episode, but that's really all there is to enjoy about it. The old spurred classmate story was silly, though the ending was a surprise.