It's the last episode until March, but I think the writers have found where they want the show to go. Initially, didn't quite have a clear footing, but with each subsequent episode, they've used the strength of the cast effectively and the writing has gotten more varied.
Britta drunk dials Jeff, leaving very awkward situation. The remedy, as Abed has learned from watching sitcoms, is to reciprocate the action. That makes the situation even worse after Jeff calls both Britta and Michelle (the statistics professor he is dating) without any knowledge of what happened. At the Valentine's dance, Jeff has no clue what to expect, and it's clear things aren't going well. Michelle is mad at him because he wanted to find Britta, and still doesn't care after he explains the situation to her. Britta shows up with a tight dress to play one last trick on Jeff. She claims he asked her to the dance, but he really didn't. That blows over quickly, and Britta bails Jeff out be playing the good portion of a 40 minute call to her. Jeff is back on Michelle's good side.
Jeff initially started off as the guy who chased Britta who was seemingly uninterested. That in itself isn't original, and was probably the weakest part of the show. Jeff asking Britta out every episode has no potential room for growth. Ever so slightly, the writers started adding different layers to Jeff, and even have him a girlfriend. Britta is Jeff's friend, and Jeff knows well enough to not be a douche to Michelle and continuing pursuing Britta. At the same time, Britta is fine with what Jeff does, but knows there's part of him that still likes her.
As far as plot goes, the episode wasn't that strong, and the subplot was pretty hokey. Pierce and Troy buy themselves Valentine's gifts, and Change jumps all over them in class, humiliating them. Annie and Shirley vow to get back at them, and create a fake letter from Princeton which Chang sees through instantly. He assumes the letter was from Pierce and Troy, so he forces them to go with him to the dance in ridiculous outfits. They go, and Annie and Shirley reveal the truth to them, but they do what Chang asks of them.