Well that was great, wasn't it? There have been comments online about how Community hasn't had the break-out episode yet this season, and indeed I would concur that there hasn't been a super-amazing episode yet on the level of a bunch of season two episodes. Community turned that sentiment around with "Remedial Chaos Theory," an episode easily rivaling the best of second season. It's a high-concept episodes, with multiple timelines and whatnot, but the characters are immediately recognizable in all their quirks and it feels very familiar.
I'm not going to go into the plot summary of each timeline since that would take forever, but what made the episode come together was the final timeline, when Jeff goes to get the pizza. He doesn't say no to Britta, allowing for her to start singing and then everyone to start dancing. There is no chain reaction of Britta getting high into all the hijinks that occurred in other timelines. This puts "Remedial Chaos Theory" along the same lines as "Biology 101," in which Jeff is placed as the outsider. I'm interesting to see what happens to Jeff this season.