Kurt and Blaine are together, as are Rachel and Finn. Blaine is over Kurt's all the time and is treated like one of the family, even welcome on Fridays for family dinner. Rachel isn't. She gets really jealous of Blaine and tries her hardest to get herself invited over. I can't remember much more. I think there was a scene where Blaine ran into the house just in time for dinner, but the family waited for him so he could shower and change.
Hope someone knows what I'm talking about; I'd love to read it again.