S9E5: The One with Phoebe's Birthday Dinner

The friends are looking forward to getting together and celebrating Phoebe's birthday. However, on the day of the party, Ross struggles to convince Rachel to leave Emma with Mrs. Geller babysitting, and Monica and Chandler get into an argument, after Monica discovers that he's been smoking. All of this causes them to be incredibly late, leaving Phoebe and Joey alone at a restaurant with a table for six.